When Drew Clarkson first arrived at Oregon State Beavers in 2014, he listened as the older Beavers offensive linemen proclaimed how only 30 to 40 percent of the freshmen would still be on the team as seniors.

Clarkson's reaction? Whatever. "We'll all be there," he remembers thinking.

The offensive line, filled with big bodies taking on contact each play, endures more attrition than most position groups. But predicting that two-thirds of the group would not make it to their season year seemed a bit excessive.

As it turns out, it was a conservative prediction.

Injuries. Cancer. Personal tragedy. Medical retirements. Oregon State's offensive line has experienced it all in recent months. Good luck finding another position group in college football with lousier luck than the Beavers' O-line. Even the team's line coach, T.J. Woods, hasn't been spared. While cleaning a room last month at the team's training camp in Bend, Oregon, Woods had a wooden bed fall on his arm, tearing his triceps and requiring him to have surgery.

"It's gotten to a point where it's almost comical," Beavers tackle Robert Olson said. "You have to shake your head, laugh it off and just try to keep moving on. It's definitely not an easy thing to do, but the good news is when you have a support system like we do, it helps getting through everything."

If football is the ultimate team sport, offensive line is its most egalitarian subclass. Linemen are linked in everything they do, from practice to games to, in Oregon State's case, overcoming adversity.

"Other positions, there's a lot more individual glory," Woods said. "The wide receivers might not do well, but 'Hey, I caught five balls for 150 yards.' In offensive line, your destiny is tied to the other four guys up front. Nobody ever says the line gave up four sacks, but boy, the left guard played great. We're kind of the unsung heroes on the team.

"We're all we've got, at the end of the day."

What are the odds?

It's a question Clarkson and Olson asked in June, when Olson was diagnosed with testicular cancer. They were both Beavers offensive linemen. They were roommates. Now Olson was facing the same fight Clarkson had in high school.

Robert Olson, right, and Drew Clarkson, middle, and Mason Johnson, left, are Oregon State roommates and teammates who have helped other through illness and injury during their college careers. Courtesy of Robert Olson

"If you did try to calculate the odds, it would be so small," Clarkson said. "It's not only the roommates thing, but the same type of cancer and the same testicle."

Both have endured more health hurdles than any 20-year-old should. Clarkson underwent surgery and chemotherapy between his junior and senior years of high school. He played his senior season just a month after finishing chemo, but the effects weakened his muscles, and he tore his hamstring several times.

A body that had previously seemed injury-proof began breaking down. After arriving at Oregon State, Clarkson suffered foot and ankle sprains. He hurt his back and shoulders. Last year, he had a concussion in preseason camp and another during a game.

"I could barely do a push-up during the season," he said.

Then in February, Clarkson underwent surgery to remove a teratoma, a tumor on one of his lymph nodes left over from the cancer. Although teratomas are initially benign, they can grow to become malignant and cause incurable cancer. Clarkson's had grown and required a surgery of more than six hours, during which his intestines were temporarily removed from his body.

He still hoped to play and targeted a return for fall camp, but he underestimated the impact of the surgery. This summer, Clarkson decided to retire from football.

"It was the hardest decision I've had," he said. "It was a culmination of being susceptible to concussions with how I played, and with the injuries, chemo -- I needed to do what was best for my body."

Arguably no one on Oregon State's campus understands Clarkson's situation more than Olson. He had left hip surgery in February 2014 after signing with Oregon State. During his freshman season with the Beavers, doctors realized Olson needed the same procedure on his right hip. After missing spring practice in 2015, Olson was ready for camp, but in the second week, he came down with a viral infection that impacted his vocal chords.

The infection cost him the season. At one point, Olson worried that he would never speak normally again. He spent several months in speech therapy.

"If you've ever seen the 'Dark Knight' movies, it was like that for three or four months," he said. "It was entertaining for a few guys I know. I've still got the nickname 'Batman' on the team."

He finally got over the infection in time for spring ball, but in the third practice, he tripped over a teammate and fell, breaking his arm. It required surgery.

The only good news? "Nothing has been concurrent," Olson said.

Olson's arm was healed by June, and he was cleared to work out, with a target of returning for fall camp. Then, "the big shock happened," he said. Cancer. Fortunately, doctors caught it early; it was Stage 1, while Clarkson's had been Stage 2. Olson underwent surgery in early July.

Clarkson spoke with Olson and Olson's parents before the surgery and went to Corvallis to help his friend for about a week after the procedure.

"It's been really great to be able to lean on him," Olson said. "He's been an amazing support system through everything."

Because Olson's cancer had a 50 percent chance of returning without treatment, he went through several weeks of chemotherapy near his home in Minnesota. He completed his final treatment two weeks ago, a week before his 21st birthday, and will be back in Corvallis for the start of classes.

A return to football would "mean the world to me," Olson said. For now, he's focused on recovering and supporting his linemates.

"I know I wouldn't have gotten through everything without the support system I have, without the O-line, without my family back here, without the people I surrounded myself with out west," Olson said. "That's the biggest thing."

Beavers lineman Brayden Kearlsey has been caring for his girlfriend since she suffered a brain injury in a car accident in March. Karl Maasdam/Oregon State

Clarkson's football career is over. Olson's is unsettled. Their other roommate, offensive lineman Mason Johnson, retired from football in the spring because of head injuries. Fellow offensive lineman Leo Fuimaono, a potential starter at center, announced his retirement this summer after he was diagnosed with spinal stenosis, a narrowing of the spine that could lead to paralysis if he continued playing.

Left tackle Sean Harlow, a 28-game starter, is expected to redshirt as he continues to recover from a fractured ankle sustained last season. Woods said the offensive line room has changed "dramatically" since he arrived following the 2014 season.

"It's been hard," second-year coach Gary Andersen said. "There's been so many different ones: cancer, a neck injury, a head injury. A lot of these kids are the O-lineman you want -- the fighter, the self-made guy, the guy putting in years to get where they need to be, strength-wise. Then they get that pulled out from underneath them."

Andersen knows the feeling. An All-American center in junior college with no injury history, Andersen suffered major knee injuries during both seasons he played at Utah. He earned a shot with the NFL's Los Angeles Rams but blew out his knee for the third and final time.

"It took me some time to get over that," he said. "So when I see kids in that situation, I tell them that story and tell them there is a time to be disappointed, but there are much more important things out there. In most cases, you have your school paid for. Let's get you moving forward. Where do we want to be in a year from now?

"These kids handled that situation way better than I did."

Oregon State's offensive line hasn't just dealt with injuries and disease. Center Brayden Kearsley has spent the past six months helping his girlfriend, Damoneisha "Dami" Calhoun, in her recovery from a car accident that caused brain trauma.

On March 9, Calhoun was driving to work on Highway 34 outside Corvallis when her Chevy Cobalt slammed into an 18-wheeler truck trying to make a turn. Kearsley had been trying to reach a friend who went to school with Calhoun. The friend told him he was stuck on Highway 34.

"He said there was a crash, and it looked like someone was dead," Kearsley said. "He sent me the picture of the crash. Immediately, I recognized the car. I was glued to the picture for probably about 10 minutes. That's how I found out."

Calhoun was in a coma for a week and needed a breathing tube for 13 days. She couldn't speak for two months. There's some occasional memory loss, but she has made significant strides in her daily rehab, with the goal of a full recovery one year after the accident.

"Everything's coming back," said Kearsley, who has known Calhoun since sixth grade and has been with her for a year and a half. "It's amazing how the brain works. I'm blessed that she's alive. It's a miracle."

Sean Harlow (with hat) is a longtime starter on the Beavers line. He's expected to redshirt as he recovers from an ankle injury. Karl Maasdam/Oregon State

Andersen sent a football signed by all the players and coaches to the hospital, and Calhoun saw it as she emerged from her coma. Kearsley spent much of the spring and summer away from the team while helping her and wasn't sure he would return to football.

But after he received an outpouring of support from teammates, especially other offensive linemen, Kearsley returned for camp and is listed as a reserve center.

"The O-line's always been the closest group, and it's good to have that, especially the stuff we're going through," he said. "This game makes everybody stronger, but the stuff that nobody sees is what makes us stronger for the rest of our lives."

Like many offensive lines around college football, Oregon State players dine together on Thursday nights during the season. They're often at Murphy's, a longtime Corvallis favorite, or Local Boyz, a Hawaiian joint close to campus.

The portions are large. So is the camaraderie.

"You think things would get a little out of control, but as a group, we've stayed really strong," said starting tackle Dustin Stanton, one of the line's few mainstays. "Any time a position group goes through those changes, it could go one of two ways. It could make your unit weaker, if guys who need to step up don't, or stronger, if guys rise to the occasion.

"It has made us stronger."

Stanton has seen young players fill the unexpected voids on the line. Redshirt freshman Blake Brandel is starting at left tackle in place of Harlow. Sophomore Yanni Demogerontas took over the starting center spot. Another sophomore, Trent Moore, has become proficient at all five line spots.

Pass protection was a problem in Oregon State's opening loss to Minnesota. The Beavers allowed four sacks and two sack fumbles, both of which resulted in Gophers touchdowns. But Stanton sees daily progress and depth starting to take shape.

"It's a growing group," he said, "and that's due to a lot of the adversity."

Andersen doesn't pressure retired players to stay involved, but Fuimaono still comes to practices and Clarkson remains in touch with Stanton and others. Olson attended the season opener in Minneapolis to support his teammates.

Woods has seen the group gain greater perspective about life.

"Coaches, myself included, can make it seem like it's the end of the world or it's everything," he said. "But the biggest lesson learned is there's a lot bigger things than football. A lot of those kids have learned that, whether they've experienced something traumatic or watched their peers go through it."

The Beavers linemen deserve a break from the trauma. But whatever obstacle comes next, they won't recoil.

"Everybody's got each other's back," Kearsley said. "Everything we've been through as a unit -- personal issues, personal battles, battles as a unit -- we've all gone through them together.

"So we're ready for anything."