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A former teammate of Pittsburgh Steelers wide receiver Antonio Brown said issues related to the superstar's professionalism have been "brewing for years."

On Friday, Jeremy Fowler of ESPN.com provided comments from several current and former members of the Steelers roster about Brown's recent falling-out with the franchise. One passed along a story about head coach Mike Tomlin telling the team why the wideout often received a pass for tardiness.

"[Tomlin] essentially told the group: 'We'll tolerate it now because of what he brings on the field, but the minute production stops, you don't overlook it,'" the ex-Steeler said.

The situation boiled over when Brown missed the team's Week 17 game against the Cincinnati Bengals.

Gerry Dulac and Ed Bouchette of the Pittsburgh Post-Gazette reported the wide receiver sat out the season finale following a practice dispute with quarterback Ben Roethlisberger, not because of the knee injury cited by the team on its injury report.

Tomlin was asked during his season-ending press conference whether distractions could ultimately overshadow a player's productivity.

"Certainly," Tomlin told reporters, adding it would handle any discipline for Brown's actions during the final week of the campaign "in-house."

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The 30-year-old Miami native remained his usual Pro Bowl-caliber self when on the field. He racked up 104 receptions for 1,297 yards and a career-high 15 touchdowns in 15 games.

Now the question is whether Brown will return to the team in 2019—he's got three years left on his four-year, $68 million contract with the Steelers—or if the front office could trade him in the offseason.

Fowler reported the market of potential suitors is "small but strong," and one former Steelers player told ESPN.com the end of the receiver's time in Pittsburgh could be near.

"This has been brewing for years," he said. "It's just now coming to the surface. And it's probably over."

If Brown is traded before the 2019 season, his Steelers tenure will end with seven Pro Bowl selections and four first-team All-Pro nods since the team picked him in the sixth round of the 2010 draft out of Central Michigan.