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ONE DAY IN April, the NFL asked Chris Borland to take a random drug test. The timing of this request was, in a word, bizarre, since Borland, a San Francisco 49ers linebacker, had retired a month earlier after a remarkable rookie season. He said he feared getting brain damage if he continued to play.

Borland had been amazed at the reaction to his decision, the implications of which many saw as a direct threat to the NFL. And now here was an email demanding that he pee in a cup before a league proctor within 24 hours or fail the test. "I figured if I said no, people would think I was on drugs," he said recently. That, he believed, "would ruin my life." As he thought about how to respond, Borland began to wonder how random this drug test really was.

What did the NFL still want with him? Nobody could have held out much hope that he'd change his mind. On Friday, March 13, when Borland retired via email, he attached a suggested press release, then reaffirmed his intentions in conversations with 49ers officials. Instead of announcing Borland's retirement, the team sent him a bill -- an unsubtle reminder that he'd have to return most of his $617,436 signing bonus if he followed through. That Monday, Borland, knowing he was forgoing at least $2.35 million, not to mention a promising career, made the announcement himself to Outside the Lines. He has since elaborated on the decision to everyone from Face the Nation to Charlie Rose to undergraduates at Wisconsin, where he was an All-American.

Borland has consistently described his retirement as a pre-emptive strike to (hopefully) preserve his mental health. "If there were no possibility of brain damage, I'd still be playing," he says. But buried deeper in his message are ideas perhaps even more threatening to the NFL and our embattled national sport. It's not just that Borland won't play football anymore. He's reluctant to even watch it, he now says, so disturbed is he by its inherent violence, the extreme measures that are required to stay on the field at the highest levels and the physical destruction he has witnessed to people he loves and admires -- especially to their brains.

Borland said that if there was an increased risk of not being able to play with his own kids someday; he didn't want to take that risk. Clayton Hauck

Borland has complicated, even tortured, feelings about football that grow deeper the more removed he is from the game. He still sees it as an exhilarating sport that cultivates discipline and teamwork and brings communities and families together. "I don't dislike football," he insists. "I love football." At the same time, he has come to view it as a dehumanizing spectacle that debases both the people who play it and the people who watch it.

"Dehumanizing sounds so extreme, but when you're fighting for a football at the bottom of the pile, it is kind of dehumanizing," he said during a series of conversations over the spring and summer. "It's like a spectacle of violence, for entertainment, and you're the actors in it. You're complicit in that: You put on the uniform. And it's a trivial thing at its core. It's make-believe, really. That's the truth about it."

How one person can reconcile such opposing views of football -- as both cherished American tradition and trivial activity so violent that it strips away our humanity -- is hard to see. Borland, 24, is still working it out. He wants to be respectful to friends who are still playing and former teammates and coaches, but he knows that, in many ways, he is the embodiment of the growing conflict over football, a role that he is improvising, sometimes painfully, as he goes along.

More than anything, Borland says he doesn't want to tell anyone what to do. This is the central conflict of his post-football life. He rejected the sport, a shocking public act that still reverberates, in tremors, from the NFL to its vast pipeline of youth leagues. Yet he's wary of becoming a symbol for all the people who want to end -- or save -- football.

We trailed Borland for five months as he embarked on a journey that drove him deeper into the NFL's concussion crisis and forced him to confront the sport in ways he avoided while playing. One day in June, he returned to Archbishop Alter High School in Kettering, Ohio, to visit with his old coach, Ed Domsitz. "We're in a period now where, for the next 10 or 15 years, many of us, we need to figure out a way to save this game," said Domsitz, a southwest Ohio legend who has coached for 40 years.

Jovial and gray-haired, Domsitz was standing on the Alter practice field, a lake of synthetic green turf. He tried to recruit Borland to his cause.

"Why don't you come back and coach the linebackers?" Domsitz asked. "We need to teach these kids the safe way to tackle."

"Some of my best tackles were the most dangerous!" Borland responded, laughing.

"You're exactly the kind of people we need," the coach insisted.

Borland lowered his head, embarrassed. "I can't do that," he said, almost inaudibly. "Maybe I could be the kicking coach."

Later, away from Domsitz, Borland explained: "I wouldn't want to be charged with the task of making violence safer. I think that's a really difficult thing to do."

In the months following his retirement, Borland has offered himself up as a human guinea pig to the many researchers who want to scan and study his post-NFL brain. He has met with the former vice chief of staff of the U.S. Army and with mental health experts at the Carter Center in Atlanta. He has literally shrunk, dropping 30 pounds from his 248-pound playing weight while training for the San Francisco Marathon, which he ran in late July.

As the Niners reported to training camp in July, Borland was examining the Book of Kells, a 1,200-year-old manuscript, at the Trinity College Library in Dublin, the start of a six-week European vacation.

In many ways, Borland is like any bright, ambitious recent college graduate who is trying to figure out the rest of his life. In other ways, he's the most dangerous man in football.

On that day back in April, Borland stared hard at his iPhone, pondering what to do about the NFL's summons to a post-retirement drug test. The league says it reserves the right to test players -- even after they've retired -- to ensure that they don't dodge a test, then return. But given the stakes, and the NFL's dubious history on concussions, it occurred to Borland that maybe, just maybe, he was being set up.

"I don't want to be a conspiracy theorist," he says. "I just wanted to be sure." Borland agreed to submit a urine sample to the NFL's representative, who drove in from Green Bay and administered the test in the Wisconsin trainer's room. Then he hired a private firm for $150 to test him independently. Both tests came back negative, according to Borland.

"I don't really trust the NFL," he says.

Borland offered himself as a subject for concussion research after he left the 49ers. He was the perfect human guinea pig -- he was alive and young and had endured hundreds of hits. Michael Zito/AP Images

TOWARD THE END of his rookie season, Borland read League of Denial, our 2013 book chronicling the NFL's efforts to bury the concussion problem. After his last game, he contacted us through former St. Louis Cardinals linebacker David Meggyesy, who also walked away from the NFL, in 1969. Meggyesy wrote a best-selling memoir, Out of Their League, in which he described football as "one of the most dehumanizing experiences a person can face." Borland, a history major at Wisconsin, had met Meggyesy during his senior year, after hearing him give a guest lecture titled "Sports, Labor and Social Justice in the 21st Century."

It's tempting to draw parallels between Borland and Meggyesy, both of whom reject the NFL's easy narrative of cartoon violence and heroic sacrifice. Late in his pro career, Meggyesy was benched for his political activism. At Wisconsin, in 2011, Borland was punished with extra conditioning for skipping class to protest Republican Gov. (and current presidential candidate) Scott Walker, who was trying to limit collective bargaining for public employees. Borland marched with three cousins, one a teacher, and carried a sign that read: recall walker.

But there are significant differences between the two men. Meggyesy linked his retirement to the politics of the anti-war and civil rights movements. Borland, a more reluctant activist, is concerned primarily with public health. "I'm not really interested in fighting anything," he says. "But there are former players who are struggling. And certainly there are kids that are gonna play in the future. So if my story can help them in any way, I'd like to find a way to do that."

Borland reached out to us back in February because, as he contemplated retirement, he hoped to speak with researchers who appeared in League of Denial. One was Robert Stern, a neurology professor at Boston University, the leading institution for the study of chronic traumatic encephalopathy, or CTE. Over the past decade, the disease has been found in the brains of 87 out of the 91 dead NFL players who were examined. In late February, a BU-hosted "consensus conference" concluded that CTE is a distinct neurodegenerative disease found only in patients who experienced brain trauma. The NFL rejected its link to football for years.

"I'm concerned to the point of contemplating retirement, despite only playing one year in the pros," Borland wrote Stern in an email. They arranged to speak by phone on March 13. According to Borland, Stern told him that he could already have brain damage "that might manifest later"; damage that could worsen as a result of "a thousand or 1,500 hits every fall for 10 years." Stern says he also cautioned Borland that the science was still limited. "He said if there was an increased risk of him not being able to play with his kids, he didn't want to take that risk," Stern recalls.

Borland says his conversation with Stern sealed his decision. He retired later that day.

Borland told Stern that he hoped to use his experience "to help science." His participation in concussion research has become a big part of his journey to find a meaningful role for himself after football. He is a highly coveted research subject because he is neither old nor dead and because he was recently exposed to NFL-grade head trauma.

One of his first post-retirement stops was a meeting with Stern.

"This is going to be a weird day for you," Stern told Borland as he began a day of testing on April 30 at the Boston University School of Medicine.

Bolted to the front of the redbrick building was a metal sign that read: TRUTH ABOVE EVERYTHING. Stern sat behind his desk in his office in a coat and tie. Like many concussion researchers, he has a complicated relationship with the NFL. Stern, who once accused the league of a "cover-up," says he now has a pending application for a $17 million CTE study funded by the NFL through the National Institutes of Health.

On this April day, Stern still seemed floored by Borland's decision.

"One of the things you asked me was, 'What do we know? What are the risks?' And I think I said about 100 times during our conversation: 'I just don't know!' " Stern told Borland, who wore jeans and multicolored Hoka running shoes and sipped coffee from a paper cup. "A decision to stop having exposure to repetitive hits to your head is, in my mind, a really, um, unbelievable decision. Not necessarily the right decision for everyone. I just wanted to make sure we're on the same page again."

"Absolutely," Borland said. "I understand correlation isn't causation and I'm just removing myself from the risks. I know I could be wrong."

Borland estimates he's had about 30 concussions throughout his football career. Michael Zagaris/San Francisco 49ers/Getty Images

"I guess better safe than sorry," Stern said.

"Exactly."

Borland was ushered into a separate room, where a graduate assistant peppered him with questions about his employment and concussion history.

Borland had said previously that he had two diagnosed concussions -- one that knocked him out during eighth-grade soccer, another while playing football his sophomore year at Archbishop Alter.

"Some people have the misconception that concussions occur only after you black out when you get a hit to the head or to your body," the graduate assistant told him. "But in reality, concussions have occurred any time you've had any symptoms for any period of time." She ticked them off: blurred vision, seeing stars, sensitivity to light or noise, headaches, dizziness, etc.

"Based on that definition, how many concussions do you think you've had?" she asked.

Borland paused.

"I don't know, 30?" he said finally. "Yeah, I think 30's a good estimate."

The exam lasted most of the day. When Stern contacted him later, he told Borland that BU could detect no current effects from his decade of playing tackle football.

Over the next two months, Borland turned over his brain to the scrutiny of several researchers -- some traditional, some not. After undergoing exams at UCLA and Johns Hopkins University in Baltimore, on May 13 he flew to Orange County, California, to see Dr. Daniel Amen, the psychiatrist who heads the Amen Clinic in Costa Mesa. Amen has treated hundreds of NFL players, many of whom swear by him. His methods are unproven, though, and some people in the medical community regard him as a quack. Borland wanted to see for himself.

Upon arriving, he found himself trailed by cameras for a show that Amen, wearing black jeans, a black T-shirt and pancake makeup, was apparently trying to sell to TV. The medical exam included a visit to the clinic's director of research, a UCLA neurobiology Ph.D. (and a former model, whom Amen said he initially included in his NFL study to attract subjects). She slipped a rubber cap over Borland's head to measure his brain's electrical activity. As the cameras rolled, Amen's wife, Tana, dressed in a red cocktail dress, declared to a bemused Borland, "What I really want to say to you is: You are a brain warrior. You're a brain warrior!"

That kind of thing happens a lot to Borland. He's so polite, so eager to be helpful, he finds himself in uncomfortable situations. "I think this whole world of brain injury and football is more political than I anticipated," he says. "And I don't want to be a part of that in any way." Borland turned down a request to promote the upcoming Will Smith movie, Concussion, and has rejected numerous endorsements. "I don't want to monetize head injury in football," he says. "I think that attacks your legitimacy to a certain degree."

Two weeks after he visited Amen, Borland drove the two hours from the Bay Area to Sacramento to participate in a fundraiser for a paralyzed semipro player. He found himself in the middle of a sad pep rally that, oddly, showcased potential concussion remedies while celebrating the sport that causes the injury. Tables manned by people touting treatments like "CranioSacral Therapy" and "Bowenwork" touch stimulation lined the half-filled ballroom of the Red Lion hotel.

"Who's got it better than us?" shouted an auctioneer, trying to fire up the crowd with the slogan made famous by former 49ers coach Jim Harbaugh.

"Nobody," the fans responded tepidly. The bidding on a Borland-signed football stopped at $500, at which point Borland, wearing tan slacks and a solid blue tie, hurled it softly to the winner. The man told Borland that he appreciated the "bravery" of his decision to retire -- then asked for the ball to be made out to his nephew, who was just starting to play high school football.

Borland wondered whether he was the only one attending the event who saw its irony. "You don't have to promote the game to help people who have been hurt by it," he said.

Part of the confusion is that, even though he walked away from the NFL, football people -- fans, players, coaches -- still consider him one of them. They find it inconceivable that someone who was so tough and played the game so hard doesn't buy into the hype, which Borland, somewhat derisively, calls "the overwhelming tide of marketing about how great and awesome football is." Borland scoffs at the oft-repeated clichés about football's unique ability to impart wisdom. "It's too bad Gandhi never played football," he said one afternoon. "Maybe he would have picked up some valuable lessons."

Borland says he loved football but never considered it "fun." "It's not a water park or a baseball game," he says. Clayton Hauck

BORLAND HIMSELF ONCE seemed as if he might have been created in an NFL factory.

He grew up in Kettering, a Dayton suburb, which he described in a paper for a UW history course as "a top down, planned neighborhood of mostly white middle-class people." Borland's father, Jeff, who played linebacker for a year at Miami (Ohio), is a plain-speaking investment adviser. Zebbie, Borland's ebullient mom, teaches cooking classes at a local market. He is the sixth of seven children (one girl, followed by six boys) who routinely battered one another in a variety of neighborhood contests until night fell and their tree-lined street twinkled with fireflies.

The Borlands are a tight-knit family of independent thinkers, with political views that run the spectrum from red to blue. "We'll get together and talk politics for six hours on a Friday night -- yelling, cussing at each other -- and the next day everybody will be fine," says Mark Borland, a Dayton attorney and the third-oldest Borland sibling. "It's almost a time-honored tradition on the holidays."

Chris went through childhood known as Little Borland, quiet and shy but also freakishly athletic and physical. "He came out ready to fight," says Joe Borland, a U.S. Army JAG officer who is 12 years older than Chris. Jeff forbade the boys to play tackle football until they turned 14, partly out of concerns about concussions. "I was always big on technique and the fundamentals," he says. "And that didn't necessarily get coached by dad coaches in peewee leagues." Chris played basketball and soccer through eighth grade, excelling against older boys, but he yearned for more contact. "Once he gets a taste of football, he's gonna love it," Jeff told Zebbie.

At Archbishop Alter, Borland did love to hit, but he was known as much for flights of improvisational genius. He played running back almost exclusively until his senior year, when Domsitz, his coach, created the Borland Rule, installing him on defense at rover whenever opposing teams crossed the 50. Borland's most memorable play, still a local legend, came against Fairmont, Alter's crosstown rival. On third and short, he launched himself over the line, turned a somersault in midair and pulled down the running back from behind as his feet hit the ground. The play has been viewed nearly 222,000 times on YouTube.

Borland was ignored by top Division I schools, who saw him as small and unremarkable. Ohio State was 80 miles up Interstate 70, but the Buckeyes weren't interested, and neither, really, was Borland. He pinned his hopes on Wisconsin, his grandfather's school. Joe took control of his little brother's recruiting. To bulk Chris up, Joe put him on a modified version of Brian Urlacher's workout program, which Joe had Googled. He shuttled him to camps and handed out highlight DVDs to recruiters.

Bret Bielema, now at Arkansas, was the coach at Wisconsin when Borland showed up at a camp in Madison. "I sat and watched him for three days, and he must have made 20 interceptions, made every play known to man, punted 60 yards, kicked 30-yard field goals," Bielema recalls. "I just sat there with my jaw dropped."

When the camp ended, Bielema invited Borland, his brother Joe and their sister, Sarah, to his office. When Bielema offered Borland a scholarship, Borland leaped out of his chair to hug the startled coach. Borland, of course, would later walk away from millions, but at the time he was so excited to play football for nothing that he celebrated in the stadium parking lot with a standing backflip.

"IT'S INTOXICATING, IT'S a drug, a drug that gives you the most incredible feeling there is," Borland was saying. "Outside of sexual intercourse, there's probably nothing like it. But fun is the wrong word for it. I don't consider football fun. It's not like a water park, or a baseball game."

It was early July, and Borland sat on the patio of the Wisconsin student union, sipping a tall beer on a warm night. The school sits between two lakes, Mendota and Monona, and boats bobbed in the shimmering water. Borland graduated in 2013, but he frequently returns to Madison.

Borland's football addiction, as he calls it, flourished on the turf at Wisconsin's Camp Randall Stadium, and ultimately, his disillusionment with the sport began there. An unknown when he arrived, he left as the Big Ten defensive player of the year. Undersized, with stubby T-Rex arms, he bludgeoned people, once hitting a Michigan State receiver so hard, Clowney-style, he separated him from his helmet and do-rag. Borland forced 15 career fumbles, one shy of the FBS record. He seemed to play in a state of ecstasy: Matt Lepay, a Badgers broadcaster, looked over at practice one day and saw Borland catching rapid-fire passes from a JUGS gun with his feet.

Bielema left Wisconsin for Arkansas at the end of Borland's junior year. He became emotional as he described receiving a handwritten letter from Borland. On one side was a list of all of Borland's accomplishments. "On the other side," Bielema said, choking back tears, "he wrote, 'None of these things would have been accomplished if you hadn't given me a chance.' "

Off the field, Borland was hard to pin down -- complex, quietly opinionated, a voice of conscience in the locker room. "I've tried to describe Chris to other guys, because guys want to know about him, and it's tough," says Mike Taylor, who played linebacker alongside Borland. "He doesn't really do anything for himself. And everything he's done is thought out -- the pros and the cons. He doesn't put people down. If there's a joke, he'll laugh, but if it's too harsh, he'd be the one to say, 'Hey, that's not funny, you shouldn't say that.' And guys would listen or shut up and say they were sorry. That's who he was." Andy Baggot, until recently a sportswriter for the Wisconsin State Journal, called Borland the most thoughtful athlete he interviewed in 37 years. In the fall semester of his senior year alone, Borland put in 125 hours at local hospitals and schools, according to Kayla Gross, who organized volunteer work for Badgers athletes. "It will probably go down in history as the most volunteer hours ever" by an athlete at the school, she says.

In fact, Borland was leading something of a double life. Publicly, he was a football star, happy and fulfilled. Privately, he was taking an increasingly critical look at his sport.

Borland began at Wisconsin as a wedge buster on kickoffs, a task he compared to "bowling, but it's people doing it." After blowing up a wedge against Wofford, he couldn't remember the rest of the game, including his own blocked punt, which led to a touchdown. That night, unable to eat, his head pounding, Borland had a teammate wake him up every few hours, fearing he'd lapse into a coma. He never told the coaches or trainers. That Monday, he was named co-Big Ten special-teams player of the week. "That's one of those things where, when you step away from the game and you look at it, it's like, 'Oh my god,' you know?" Borland says. "But it makes sense to you when you're 18 and you've dedicated your life to it and the most important thing to you is to get a good grade on special teams."

Near the end of his freshman year, Borland discovered Toradol, the controversial painkiller used widely in college and the pros. "It was life-changing," he told the BU researchers, chuckling, when they took his medical history. The U.S. Food and Drug Administration warns that Toradol should be used sparingly, for severe acute pain. Borland, who had shoulder surgery three times while at Wisconsin, said he would sometimes use the drug every other game.

Some of Borland's teammates were worse off, and that concerned him more. Taylor, his close friend, was also one of the best linebackers in the nation, twice all-conference, a future pro. But it became harder and harder for Taylor to stay on the field. In 2011, he tore his meniscus on a blitz against Minnesota. The Monday after the game, he had knee surgery to remove half of it.

The next Saturday, with Wisconsin fighting for the Big Ten title, Taylor played against Illinois. "I remember that morning I was thinking, 'This is f---ing stupid. What am I doing?' " he recalls. "They shot Toradol in my ass. And I remember covering up my knee with bandages, just so I couldn't see blood. The first half was shaky for me. If you watch the game film, it's like, 'This dude should not be playing football.' "

Taylor says no one tried to stop him. "I think it was mostly my fault," he says. "I was waiting for them to say, 'Hey, you're out of here. This is kind of sad. And not smart.' But I was kind of in a position to dictate. I guess the coaches had trust in me." He thinks he took another shot of Toradol at halftime.

"After the game, I finally took everything off, and there was just blood dripping down," he says. "The hair was matted down because of all the compression on it, the tape, the glue, and there was still blood coming down. I remember the coaches coming by, going, 'Great game! Can't believe what you just did!' "

The next season, Taylor developed a hernia but continued to play. Wisconsin faced Stanford in the Rose Bowl that year. "I'm just laying on the table before the game, buck naked, just taking shots of s--- I don't even know," he says. "Taking pills, putting straps on, putting Icy Hot on. People were coming in and looking at me like I'm a f---ing robot, like I'm dead."

Taylor had surgery after that season. After recovering, he signed with the Seattle Seahawks, but he is currently unable to play because of a bone condition in his hip and has been waived. He is 25 and has had 10 surgeries. (Wisconsin declined to comment specifically on Borland or Taylor but said in a statement that injured athletes are allowed back on the field only after medical staff deem them "fit to return." The school added, "The limited usage of Toradol is administered by our team physicians and closely monitored.")

Taylor says he and Borland often joked about their injuries. "You might be in so much pain that you'd just be laughing because it was so stupid what we were doing," he says. "I think after a while, Chris just thought, 'This is stupid, this is stupid, this is stupid.' And it got to the point, with his head, where there was just too much stupid going on. And he finally left."

Asked whether he thought Taylor's characterization was fair, Borland replied: "Yeah."

"People make the analogy to war a lot, and I have two brothers in the Army," Borland says. "Getting a TBI [traumatic brain injury] and having post-traumatic stress from war, well, that's a more important cause. Football is an elective. It's a game. It's make-believe. And to think that people have brain damage from some made-up game. The meaninglessness of it, you draw the line at brain damage."

Borland rarely shares his concerns with other players, not wanting to preach or judge. The public nature of his decision is the most uncomfortable part for him. "I think sometimes people don't know how to act around me now," he says. "Sometimes I feel almost like I'm consoling people, you know? Like, 'Hey, it's gonna be OK.' "

He has come to dread public events connected to football, where people are likely to tiptoe around his decision, as if he has an illness, or, worse, they lecture him about football.

On July 9, Borland drove in his family's Honda Accord from Madison to Chicago for a UW fundraiser. The night was warm, and Wisconsin alums filled the terrace of the Chicago Club, overlooking Lake Michigan. "I'm not ready for this," Borland said as he walked off the elevator to the murmur of hundreds of people.

In a corner, attendees struck the pose next to Ron Dayne's Heisman Trophy. The tables were covered with UW football helmets, white and Badgers red, and four cheerleaders mingled in the crowd.

Borland had just arrived when he ran into a prominent alum, Wade Fetzer.

"Soooo," Fetzer said. "You're going through a big transition."

"Yeah," Borland said.

"But this is a huge issue. And you brought it to a head!"

Borland went straight to the bar and ordered a vodka and lemonade. People descended on him, friends, old teammates, and soon he was at ease. As part of the event, Lepay, the Badgers broadcaster, interviewed Wisconsin athletic director Barry Alvarez, who coached the football team for 16 years. Lepay asked Alvarez about the college football playoff system, the search for a replacement for retiring basketball coach Bo Ryan, the importance of recruiting good students. There was no mention that one of the finest football players in the school's history had recently abandoned the sport.

Later, as the evening wound down, we asked Alvarez about Borland. He sounded slightly defensive. "It was never an indictment against football," he said. "He just chose not to play, and I respect that decision. But there was never an indictment of football."

For his part, Borland seemed sad as he described the conflict he has created.

"On one level, it's great to see everybody, and these are my best friends in the world," he said. "And then on another level, there is this issue at hand. I'm the human representation of the conflict in their mind. And that might never change."

"I'm conflicted," Borland says. "I don't want to tell a 16-year-old who's passionate about playing football to stop, or his parents who are passionate to stop. But I don't know if I'll have my kids play either." Clayton Hauck

SHORTLY AFTER HE was drafted by the 49ers in the third round last year, Borland attended the annual rookie orientation put on by the NFL. The league tries to prepare young players for what to expect on and off the field, and it brought in two prominent retired players to give the rookies advice.

"Get yourself a fall guy," Borland says one of the former players advised. The former player, whom Borland declined to name, told the rookies that if they ran into legal trouble, their designated fall guy would be there to take the blame and, if necessary, go to jail. "'We'll bail him out,'" Borland says the former player assured them.

Borland was appalled. "I was just sitting there thinking, 'Should I walk out? What am I supposed to do?' " he recalls. He says he didn't leave the room because he didn't want to cause a scene, but the incident stayed with him.

Borland's only connection to the NFL now is through his friends and his bank account. His financial situation isn't desperate, but it's not what many people think it is. The 49ers paid him $420,000 in salary last year (the NFL minimum) plus his $617,436 signing bonus. Minus taxes and contributions to his charitable trust, he took home about $550,000 -- but still has that bill for more than $463,000 of his signing bonus. Borland, who led the 49ers in tackles last year, used a performance bonus to pay the first installment and still owes more than $300,000, due over the next two years. (It helps that Borland is the Donald Trump of frugality. Despite grossing well over $1 million last year, he rented a room in a Silicon Valley condo for $800 a month. One night he was FaceTiming with his mother, who got a glimpse of the bare walls, the reading lamp on the floor. "Chris, are you in the hospital?" she asked.)

In his own quiet way, Borland is presenting a counter-narrative to the one presented every week during football season -- the narrative created by five TV networks, including ESPN, and myriad websites, publications and talk shows ... the narrative that only $10 billion in revenue can buy. Whether you agree with him or not, the effect is like stepping into a different reality.

Shortly after he retired, Borland was invited to attend the National Summit on Sports Concussion in Los Angeles. Once he accepted, the organizers used his name ("Chris Borland, former NFL player") to promote the event. Borland told them to stop. He didn't want to be seen as endorsing the idea that football can be made safe.

The morning of the conference, about 150 trainers, neurosurgeons and biomedical engineers gathered in a large room at the Renaissance Hotel. Borland, reluctantly, had agreed to make a few remarks to kick off the event, along with Ryan Nece, the former Tampa Bay linebacker.

Nece exhorted the researchers to make football safe. "It is our responsibility to use our expertise and our experiences to find ways to make the game safer, better, stronger and more exciting," he told them. "Because of the power in this room, that can happen."

No, it can't, Borland told the researchers, contradicting Nece and, by extension, one of the main reasons behind the conference. "I made a decision a few months ago to walk away from football based on not only what I'd come to learn but also what I'd experienced," he said. "The game may be safer; you can make an argument about that. My experience over my five years at Wisconsin and my one year in the NFL was that there were times where I couldn't play the game safely. There are positive measures we can take ... but on a lead play, on a power play, there's violence."

Borland says distancing himself from the sport has helped him see it more clearly. And he is more disturbed by what he sees. One night, before he drove to Stanford to hear Meggyesy speak, we joined Borland for dinner at a Palo Alto taco joint, Tacolicious. He wore a hoodie and jeans and looked like a grad student. (The only vestiges of Borland's NFL body are his calves, which still resemble footballs, in size and shape.) The conversation turned to Meggyesy's exposé of the NFL and its characterization that pro football is dehumanizing.

The following exchange occurred:

Question: "Do you agree?"

Answer: "Well, the combine is about as much as a human being can be treated like a piece of meat in 21st-century America. You walk onstage in your underwear. You walk room to room, where sometimes five doctors are pulling on different parts of your body while you're in your underwear and talking about you like you're not there. So, yeah. I mean, it's like cattle. They're in the cattle business. It's how well your body can perform."

Question: "But you obviously love the sport. So how do you reconcile that feeling with the parts that you love?"

Answer: "I think by compartmentalizing. I would say, 'This comes along with it.' At times I would think, 'How can I slam this guy in his face and then be a gentleman Monday through Saturday?' By compartmentalizing and then going to that place on game day. But I don't think there's any such thing. If you're violent, you're violent."

Question: "Do you think the game brings out things in ourselves that are already there?"

Answer: "I don't know if Aristotle's [Catharsis] theory -- that we're still really hunter-gatherers, with fangs and eyes in front of our skulls -- I don't know if [football] finds an outlet for that or it promotes that. If it's natural, maybe we should express it in other ways, not necessarily partaking in the violence. Because that's what the game is sold on. I don't know if we should promote that. I don't think we should bury it either, but maybe we should find another way to express our physical nature."

For now, that's as close as Borland will come to saying football should be banned. But he thinks the NFL's current mantra -- making football safer -- is silly and pointless. Once you admit that, he believes, it's merely a matter of how much risk you're willing to take by playing.

The concussion that led Borland to retire came on a routine play, and that's precisely his point: Unlike riding a bike or driving a car, where head injuries occur by accident, in football the danger increases by doing everything right. During a preseason practice, he stuffed the lead blocker, 6-foot-4, 293-pound fullback Will Tukuafu. Borland -- 5 inches shorter and 50 pounds lighter -- buried the crown of his helmet into Tukuafu's chin and stood him up. He walked away dazed for several minutes. He began to wonder how many times his brain would be subjected to the same injury and what the lasting effect might be.

"It raised the question, 'When will it stop?' " he says.

In February, Borland's sister, Sarah, his oldest sibling, sent him an article on Boston University researcher Ann McKee, who warns that "sub-concussive" hits -- the kind that occur on every play -- might be the primary cause of brain damage in football.

"I'm way ahead of you," Borland wrote back.

Now, five months after his historic decision, Borland finds himself whipsawed by football's various stakeholders. It can leave him indecisive and, at times, uncertain where to turn. "It's not a fun thing to do, completely miserable, really," he said one day. "You just catch s--- constantly, for the most innocent things." When the BU-affiliated Sports Legacy Institute recently asked him to endorse its campaign to eliminate heading in youth soccer, Borland agonized over the decision. Eventually, he agreed because "personally it makes a lot of sense to me. I just don't want to be that guy who rains on everyone's parade. I love sports so much and grew up playing every sport under the sun, and it was pure bliss. To fundamentally change a sport or to encourage people to do that, it's a little intrusive."

He says he knows some people probably blame him for contributing to the "pussification" of football. "I think in the eyes of a lot of circles, especially within football, I'm the soft guy," he says. "But I'm fine with being the soft, healthy guy."

Both of Borland's parents seem done with football. "I'm just watching car crashes; I don't even see the game," Jeff says. Zebbie says she recently read a book set in ancient Rome and "it was so similar to the football stadium, with all the fans cheering in the background and bringing the gladiators in. And I thought, 'We're just repeating history, over and over again.' It's an American pastime, but it's hurting people. So it's not worth it anymore to me." The question is how far their son will be willing to go.

"I'm conflicted," Chris Borland says. "I don't want to tell a 16-year-old who's passionate about playing football to stop, or his parents who are passionate to stop. But I don't know if I'll have my kids play either. I don't think it's black-and-white quite yet." Recently, a friend of Borland's mother sought guidance from him on whether her son should play football. Borland said he was comfortable providing information but not advice. "I'm not going to help people parent their children," he says. "I took the stance personally to not do it; I walked the walk. But it's not my place to tell anyone else what to do."

His father isn't so sure. "Somebody sooner or later is going to ask him, 'Yes or no?'" Jeff says. "Just, 'Yes or no?' And you are going to have to answer it."

ON JULY 30, as the 49ers prepared to open training camp, Borland touched down in Cork, Ireland. He was planning to spend six weeks in Europe. He carried with him one pair of black pants (which he was wearing), six shirts, six pairs of underwear and socks, stuffed into a black backpack with his iPod (nano), laptop, journal and a Kindle, on which he was reading The Metamorphosis, the Franz Kafka novella.

Borland walked to a nearby Travelodge, pausing to take a picture of a life-size statue of Christy Ring, a local hurling legend. There will be no statues built for Borland, of course, and that seems fine with him. Informed that the Travelodge was booked, he decided to walk five miles into Cork, which is not unlike landing at LaGuardia Airport and deciding to walk into Manhattan.

Nights in Cork are brisk. Borland, who had no jacket or sweater, cloaked himself in a beige British Airways blanket he had taken off the plane. He spent the entire night walking the charming Irish city, listening to Van Morrison, crossing the River Lee, climbing the hills dotted with row houses bathed in pastels, a sensation he described, euphorically, as "floating."

Borland said it's a coincidence he decided to leave the States at the exact moment our fevered obsession with football begins anew. But you have to wonder. Had Borland stayed in football, he would have been a big part of the 49ers' fall story; you could have written it in your sleep. Now someone else will have to replace Patrick Willis, who retired a week before Borland, and someone will write that story. Borland, meanwhile, was in Europe, alone and anonymous.

Borland paused when he was asked what he wants the rest of his life to be. "That's the hardest question in the world," he said one afternoon while eating lunch in Edinburgh, Scotland. "It's like, 'What's the meaning of life?' I just want to be honest. There's no worldly possessions that really excite me. I don't need prestige. I just want to do something where I can feel confident that I'm making the world a better place."

During the summer, Borland was driving from California to Ohio when he picked up an audiobook of Jimmy Carter's Beyond the White House: Waging Peace, Fighting Disease, Building Hope. The book mentioned Rosalynn's Carter's mental health initiative. Borland was so moved he cold-called the Carter Center in Atlanta and arranged a meeting, which he called "one of the best days of my life." He is cutting short his trip to attend a September symposium there.

It seems clear that Borland is seeking a role at the intersection of football and mental health, at least for the time being. That is not good news for the NFL. Not everyone will agree with Borland. People will call him soft and accuse him of trying to ruin the national sport. But many will listen. Last December a poll conducted by Bloomberg Politics revealed that 50 percent of Americans would not want their sons to play football. Borland's decision has loomed over a spate of recent early retirements, including Patriots offensive lineman Dan Connolly and 49ers offensive tackle Anthony Davis, who said he was taking at least one year off. It's hard to ignore a man who walked away from millions of dollars simply because he thought football was bad for his health and, in the end, morally suspect. What parent wouldn't stop to listen, if only for a moment?

And, as anyone can see, the non-football life agrees with him. "This is like a movie, like it's not even real," he said, standing next to the remains of a 16th-century castle on the Scottish coast in the late afternoon. Rain, pouring out of slate clouds, lashed the Firth of Clyde and the deep green hills, but everything was somehow cast in an unearthly glow.

The night before, Borland had been out drinking in Dublin. He found himself at a packed oval-shaped bar, Millstone, near Trinity College, sampling ales and whiskey. Behind him was a friendly, low-key bachelor party, and soon he was introduced to the group. One man, a Brit named Matt, bought him a glass of Midleton Very Rare, an expensive Irish whiskey, and explained that he worked for TaylorMade, the golf manufacturer.

"So, what is it that you do?" Matt asked Borland.

Borland paused.

"I'm between jobs," he replied.

Dave Lubbers, a producer in ESPN's Enterprise and Investigative Unit, contributed to this report.