It was at the beginning of practice three seasons ago when Steelers players say they knew trouble was coming.

Star wide receiver Antonio Brown appeared with two people in tow. They were part of Brown's new social media team and were following and recording him throughout practice.

Some veteran players were stunned. It wasn't just an unusual sight; it was unprecedented.

Brown's social media adventures would continue that winter. In January 2017, without Mike Tomlin's knowledge, Brown put the coach's postgame address to the team on Facebook Live, a video that left Tomlin answering unexpected questions about why he called the Patriots "assholes" days before the team was to play those Patriots in the AFC Championship Game. Brown's move was universally condemned by numerous people in the NFL, but inside the Steelers, it didn't come as a surprise. Many in the organization—including teammates, coaches and some members of the front office—believed Brown had started living by his own set of rules months before.

Yet Brown was simply following in the footsteps of his quarterback, Ben Roethlisberger, who had operated on an island for years under Tomlin. Roethlisberger wasn't required to stay at the team hotel for home games like his teammates. He also openly criticized them on his local radio show and often ignored them by showing up late to team meetings. All with few repercussions from the Steelers.

Many players on the team had come to accept this. Brown, as well as star running back Le'Veon Bell, did not. Brown would openly tell teammates how Roethlisberger had his own set of rules while the receiver justified his own behavior over the past few years, according to current and former Steelers players. Brown ripped the 15-year veteran quarterback privately, too, once calling him, according to two team sources, "a fucking phony."

The distrust followed all three into last season. As his holdout dragged on for weeks, Bell, team sources maintain, began to echo what Brown had claimed: that Roethlisberger had long operated in a different world than the rest of the team. "If Ben didn't think he was getting paid enough, he'd do exactly what I'm doing, and not a single Steelers fan would have a problem with it," Bell told one teammate.

Tomlin was caught in the middle of the bitter feelings that were tearing the Steelers apart. It's difficult enough for a head coach to handle one or two superstars on offense. In this case, the team had three in Roethlisberger, who will enter the Hall of Fame one day, Brown, who will likely follow him, and Bell, one of the best running backs of his generation.

But Steelers sources say Tomlin didn't help himself when he sided solely with one of those stars: Roethlisberger. In doing so, as one former Steelers defensive player said, "Tomlin created a monster."

On the contrary, Tomlin supporters—a group that includes coaches around the league as well as members of the Steelers front office—argue the biggest reason for the end of the Big Three was not the dynamic between the players and their head coach, but the increasingly selfish and destructive behavior of Brown. Still others who have worked with Tomlin, such as former offensive coordinator Todd Haley, say Tomlin did a solid job of bringing all of the different egos together.

What's not debatable is that the potential of three of the NFL's biggest stars was eventually swamped by a sea of bitterness, resentment and a desire for independence in a sport that requires togetherness. And one of the game's most respected coaches struggled—and perhaps failed—to manage it all.

Roethlisberger, Brown and Bell each pushed against football norms—wrecked them—and it forced the Steelers to use their only option, which was break up a group that won 62 regular-season games over six seasons but failed to win the Super Bowl many expected such a talented team would.

Tomlin and Roethlisberger have a close relationship. Throughout their tenure together, it has been common for them to go to dinner on Fridays during the season. In many ways, that makes sense. A coach and a quarterback need to be in sync. But in Pittsburgh, the relationship between Roethlisberger and Tomlin inserted a wedge between quarterback and team, giving Roethlisberger an autonomy that perhaps no other player in franchise history possessed, a leeway that many felt made him untouchable.

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Roethlisberger exerted his power not only in the huddle but also outside the stadium. In the final moments of a brutal November loss to Denver last year, Roethlisberger was intercepted in the end zone on an attempted pass to Brown. On his local radio show days later, Roethlisberger spread the blame for the pick to Brown.

"I told him, 'You have to come in flat,'" Roethlisberger said. "'You can't drift in the end zone.'"

Brown wasn't the only target. On the same show, Roethlisberger criticized the team's play-calling, as well as rookie receiver James Washington, who attempted to make an outstretched catch only to have the ball pop loose when he hit the ground.

"You're not going to be out there," Roethlisberger said on the show, "if you're not going to make those plays for us."

When one source close to the situation was asked about Tomlin's reaction to the way Roethlisberger called out his teammates, the source said of the coach: "He let it go."

Brown didn't, which wasn't a surprise given how he had spent most of the season quietly feuding with his QB. The two barely spoke to each other, according to a former Steelers player and coach. At least not directly. While Roethlisberger would criticize Brown to teammates, calling the receiver selfish, Brown would say the same about Roethlisberger, also through players in the locker room.

By the end of last season, the situation was boiling over. The Pittsburgh Post-Gazette was the first to report that, on the Wednesday leading up to the regular-season finale on Dec. 30, Brown got into a heated argument with Roethlisberger during practice, bolted from the facility and then refused to practice the remainder of the week. When Brown showed up Sunday for the game against Cincinnati, Tomlin told him he wouldn't play.

Several Steelers players say Brown's rebellion last year in particular took them aback. "I've never seen a guy transform so quickly, from good dude to a dude I didn't recognize," one Steelers player says. "He's someone I still admire. He was trying to change the way players are perceived. He just went about it the wrong way."

Indeed, that wasn't what anyone expected from Brown when Pittsburgh drafted him in 2010. At Central Michigan, he was viewed by NFL scouts as an athletic, gritty talent who was also well-liked by college teammates.

One scouting report referred to Brown as "selfless."

After nine years, however, Tomlin and many in the Steelers organization—from ownership to coaches to players—felt Brown was uncoachable. (It was a feeling not unlike what the Raiders are experiencing as multiple reports Thursday detailed how Brown and Mike Mayock, the team's general manager, got into an altercation after Brown posted a letter on Instagram from the Raiders that informed him of tens of thousands of dollars in fines.)

Brown's benching had a more dramatic impact on the offense than is generally known. Brown plays the X receiver position, and because of his absence, JuJu Smith-Schuster had to play it. But Smith-Schuster had rarely done so, current and former team sources say, so both he and the offense had to make massive adaptations on the fly.

That, several team sources say, was one big reason Smith-Schuster was named the team's MVP last year and not Brown—even though Brown led the Steelers with a franchise-record 15 touchdowns. With all of the turmoil Brown's actions created, Smith-Schuster never once complained, earning the vote of his teammates for the award.

The Steelers' other missing star, Bell, also didn't hide his frustration over his relationship with Roethlisberger. While holding out last season, the running back stayed in contact with a number of Steelers players. Inside the locker room, Bell was viewed as one of the team's nicest players and best teammates. But when it came to the QB, Bell made his feelings clear, and they weren't so dissimilar to Brown's. "Ben demands loyalty," he told one Steelers player during last season, "but doesn't give it in return."

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After six seasons together, four playoff appearances and three AFC North wins, the Steelers' Big Three were breaking apart after years of ego mismanagement. "Ben thought, I made both of you," said one current Pittsburgh player, who asked not to be identified out of fear of repercussions from the team. "Antonio would tell us, 'I made Ben.' Le'Veon would say, 'I made both of them.'"

The only person who could bring the three together, Tomlin, had made his point of view clear, even if he didn't say it. The coach believed Roethlisberger was more valuable than Bell, and Brown wasn't worth the headaches he caused, Steelers sources familiar with Tomlin's thinking said. Bell and Brown declined to comment for this story. A Steelers spokesperson said Tomlin and Roethlisberger have publicly stated they have moved on from discussing people who are no longer on the team.

But Haley, who coached Pittsburgh's offense for six years under Tomlin, said his former colleague didn't transform into a coach who handed the franchise keys to Roethlisberger.

Haley added that what impressed him the most about Tomlin was how he was able to capably manage all of the various egos on the team, and that included Roethlisberger, Bell and Brown.

"I think he did about as good of a job as you could do," said Haley.

However, numerous sources portray a sharply different picture, one that didn't comport with Steelers history. To understand just how jarring the very public dissolution of The Big Three was for the franchise, you have to understand how much Tomlin changed the Steelers' culture, and how much the 21st-century athlete changed the Steelers.

Chuck Noll etched into the Steelers' DNA that the team came first. He led the franchise to four Super Bowl wins in 23 years while espousing a style of football derived from the game's origins—tough, gritty and well-disciplined. Like his team, he was dogged and relentless, so much so that while quarterback Terry Bradshaw respected Noll, he also hated him. Most players, in fact, had a healthy fear of Noll. Or they didn't know him well because he purposely kept a significant emotional distance from them.

"I worked there 13 years, and I know nothing about him," late Steelers defensive end L.C. Greenwood once said of Noll, according to Michael MacCambridge's biography Chuck Noll: His Life's Work. "The only time I went into his office was when he cut me."

When Bill Cowher became the coach in 1992, he reflected the changing times by being closer to players and giving them more leeway to express themselves in the locker and meeting rooms. Cowher believed, however, that veterans were key transitional cogs, and he gave many of them immense power to police the locker room. There was also tremendous respect for them.

Once, he told an aging Jerome Bettis that his 13th season in 2005 would be his last. Bettis appreciated Cowher's honesty and the fact that Cowher told Bettis this to his face. Bettis starred that entire season, helped win Super Bowl XL in his hometown of Detroit and retired with dignity.

The Steelers, like other franchises, used veterans to pass down the knowledge of the game from one generation to the next. This is how power in a locker room is transferred. It's not given by a coach. It's earned in play and battle.

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Tomlin also was known as a player's coach when he took over the team in 2007. He arrived having built a respected reputation for his work ethic and ingenuity.

As an assistant with the Buccaneers, he was often one of the first coaches to arrive at the office and the last to leave.

"He was energetic and smart," Hall of Fame coach Tony Dungy remembered. "He always had a ton of ideas. He was someone that even at a young age showed maturity beyond his years."

When Dungy was fired and Jon Gruden became Tampa Bay's head coach in 2002, he retained Tomlin. Gruden liked him instantly.

"Man, we used to call each other out," Gruden told 93.7 The Fan in 2018. "We used to go after each other on the practice field. He's, as you know, he's a fun guy to be around. He's got a great enthusiasm for football; he's a tremendous leader. A great competitor, man. He wants to win every drill; he wants to win every single thing that he goes up at you against. It brought out the best in me, and I think it brought out the best in him. ... We had some fun battles."

Tomlin's 2007 hiring in Pittsburgh couldn't have gone better. A wild-card loss in his first season prefaced the organization's sixth Super Bowl win the next year. Roethlisberger clinched the title with a six-yard touchdown pass to Santonio Holmes with 35 seconds remaining in the contest. The Steelers won 27-23.

Tomlin then had that most rare of commodities: a multiple-Super Bowl winner at quarterback. When he looked around the league and saw how quarterbacks were dominating it, he thought, I now have mine, two Steelers sources who had spoken to Tomlin on the subject said. He then didn't just give Roethlisberger power, these sources believe. He gave him all the power.

It wasn't only that Roethlisberger had more control of play-calling than most quarterbacks. Roethlisberger's influence was bigger. The way he carried himself had an impact on the team's culture that some veterans found troubling.

When Roethlisberger started to make a habit of either showing up late to team meetings or just a few minutes before they began, Pittsburgh's veteran leaders took notice. Most veterans were at the team complex early, sometimes an hour or more before a meeting started.

Not surprisingly, Roethlisberger's tardiness became an issue for the team's players council—a small group of veteran leaders that met away from coaches and the rest of the team to hash out problems among the players. Eventually, the council decided to address the issue with Roethlisberger, but before that happened, star safety Troy Polamalu informed Tomlin that they were going to talk with the quarterback.

Tomlin, however, informed Roethlisberger before the players could speak with him. The heads-up was seen by players as a massive breach of protocol and so severe that some players felt they could no longer trust their coach.

After being told of the rebuke to come, Roethlisberger went to Polamalu.

"I'm not late for stuff," Roethlisberger said.

"Yeah, you are, all the time," Polamalu responded.

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Not long after, the venerated Polamalu came to understand the protections afforded Roethlisberger did not extend to other vets. Even a player as venerated as him.

Early in 2015, Polamalu received a voicemail from Tomlin.

The 12-year veteran was being cut, went the message, according to a person familiar with the call. Tomlin apologized and then hung up.

Polamalu was angry Tomlin didn't deliver the news in person. Rather than trying to catch on somewhere else after spending his career in Pittsburgh, Polamalu retired that April. He still lives in the area but has told Steelers players and others he will never return to the team until Tomlin is gone.

Few inside the locker room, sources say, felt Roethlisberger was ready to lead the team in place of those departed veterans. He wasn't known as a studier or leader, and players didn't believe Roethlisberger had the maturity to handle all of the complexities of the position, including setting an example for other players.

It wasn't long before Roethlisberger began taking advantage of his status, players say, and when he did, Tomlin didn't push back.

Haley, who has clashed with players at several stops, also clashed with Roethlisberger. In December 2017, according to Jason La Canfora of CBSSports.com, Roethlisberger asked Tomlin to put a buffer between him and Haley on the sidelines.

The buffer Roethlisberger wanted was quarterbacks coach Randy Fichtner, who left the coaches' booth and went to the sidelines. Roethlisberger told 93.7 The Fan the move had nothing to do with Haley, but few inside and outside the organization believed that.

Such a request, said one NFC offensive assistant, is highly unusual. That the head coach granted it, this person said, was even more odd.

"No player should be able to dictate what a coach does with his assistants," the coach said.

To be clear, quarterbacks have a great deal of power, and they are the centrifuges of any team. But it cannot be stressed enough how some coaches across the league believe Tomlin is playing with fire. Every quarterback, they say, even Tom Brady, has head-coaching guardrails. Some coaches believe that giving Roethlisberger that much power will eventually burn Tomlin.

When asked if Tomlin surrendered too much power to Roethlisberger, former Steeler Ryan Clark, who played under Tomlin and was teammates with Roethlisberger and Brown, said the wrong question was being asked: "I wouldn't say 'surrendered power' as much as 'empowered him.' He always wanted Ben to be the leader. I felt like he thought Ben had to be if the team was [going] to win."

Indeed, some feel Roethlisberger has used his influence for the good of the team.

Offensive lineman Alejandro Villanueva told the Pittsburgh Post-Gazette last month that "Ben ... transmits a ... competitive edge to the players," while receiver James Washington told the paper this past spring that Roethlisberger spurred him to raise his game in the second half of last season, even if it wasn't in a touchy-feely way.

"Ben had a talk with me, and it really helped me a lot," Washington said. "I was able to be more relaxed and play the game that I've being doing since I was a kid. It was good to have that talk. He hadn't given up on me, because in my eyes it had felt like that. When he [talked to me], it was like a second [set of] lungs. Every day he challenged me. It was like he gave me tough love. He explained things to me. And he kept believing. I appreciated it."

No question, there's a different side to Roethlisberger than the one presented publicly by some teammates. But to those more skeptical teammates, Roethlisberger didn't motivate as much as divide the team.

Since the breakup, Roethlisberger, Brown and Bell have said little publicly about one another—that is, until recently. Roethlisberger told NBC's Michele Tafoya in an August interview that he regretted calling out Brown for that infamous wrong route.

"I wish I wouldn't have done it," Roethlisberger said. "Obviously, we saw what happened, and obviously, it ruined a friendship. I just got caught up in emotion and the heat of the battle."

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Brown almost immediately took to Twitter and blasted Roethlisberger, saying they were never truly close.

"Never friends just had to get my ends.......shut up already," Brown said in a since-deleted tweet.

Roethlisberger has also said that, despite losing Bell and Brown, the NFL underestimates the Steelers offense at the league's own risk.

"We're still the Pittsburgh Steelers," he told reporters in June.

Bell has also weighed in, subtly acknowledging in a recent Sports Illustrated interview the belief of some within the Steelers organization that Roethlisberger has acquired virtually unchecked power and wielded it liberally.

"The organization wants to win. Tomlin wants to win," Bell said. "Ben wants to win—but Ben wants to win his way, and that's tough to play with. Ben won a Super Bowl, but he won when he was younger. Now he's at this stage where he tries to control everything, and [the team] let him get there. So if I'm mad at a player and I'm not throwing him the ball—if I'm not throwing AB the ball and I'm giving JuJu all the shine or Jesse [James] or Vance [McDonald] or whoever it is, and you know consciously you're making your other receiver mad but you don't care—it's hard to win that way."

"AB isn't the only bad guy in the situation," Bell said. "Ben isn't the only bad guy, either. It's not just one person. It ain't just me. It's everybody."

Brown added during an episode of HBO's The Shop this summer that Roethlisberger "feels like he's the owner" of the Steelers, a view that Pittsburgh general manager Kevin Colbert helped feed when he told reporters in February that Roethlisberger is the unquestioned leader of the team and has "52 kids under him."

Tomlin has been more philosophical about the departure of Brown and Bell.

"It was no slight against those guys, but all journeys come to an end, and their journey in Pittsburgh did," Tomlin told ESPN. "I know they're not looking back, and neither are we."

Tomlin has also downplayed the fact that there was significant drama in the locker room last season.

And now, here they are, coach and quarterback, intertwined and reliant on each other, for better or worse.

In losing Brown to the Raiders and Bell to the Jets, Tomlin has total control of the team for the first time in years. That's because everything is flowing through Roethlisberger again. Only now, it's doing so without resistance from Brown and Bell.

"He's riding or dying with Ben," one source close to the situation said.

There is, players say publicly and privately, peace inside the organization now that Brown and Bell are gone.

"It's a lot different just because of the fact that the players don't have to answer those questions anymore," Steelers analyst and former Pittsburgh quarterback Charlie Batch said on the radio show Taz & The Moose. "You see the calmness coming out of the offseason program. Guys are a lot more wired in. The focus around here is, 'Why did they miss the playoffs? How come this team, as talented as they are, missed the playoffs?' They want to right that ship, and they want to get back on the right course."

There are, however, numerous remaining questions. Does the peace translate into winning? Or does the loss of so much talent mean the Steelers won't be as good?

What's clear is Roethlisberger no longer has rivals for his power. There is no star running back holding out. There is no star receiver storming out of practice.

There is just Roethlisberger and Tomlin.

For now, that's exactly how they like it.

Mike Freeman covers the NFL for Bleacher Report. Follow him on Twitter: @mikefreemanNFL.