"He and I met yesterday for an extended period of time," Tomlin said Wednesday, according to ESPN.com's Jeremy Fowler. "I'll leave the nature of that conversation between us. There was discipline involved for his missed meeting on Monday."
Brown's unexcused absence followed a Week 2 loss that saw the wide receiver and offensive coordinator Randy Fichtner engage in a heated discussion on the Steelers sideline. Brown finished the game with nine receptions for 67 yards while garnering 17 targets.
The All-Pro's frustration spilled over onto social media Monday when he tweeted, "Trade me let's find out" in response to former Steelers public relations staffer Ryan Scarpino, who suggested Ben Roethlisberger was the reason for his success.
Brown's agent, Drew Rosenhaus, later issued a statement to ESPN's Adam Schefter regarding his perceived displeasure with the team.
"The tweet yesterday was not in reference to anything other than Antonio responding to a person he knows," Rosenhaus said. "It was not directed towards a trade, or wanting to be trading. Any idea he was asking for a trade is not accurate.
"Antonio had a personal matter. I talked to the team about it. His issue was unrelated to the tweet or his relationship with the team. Third, AB has an incredible drive to win. He just wants to win. That's all that that is."
For his part, Roethsliberger has downplayed any sort of rift between Brown and the club.
"He's the best in the world," Roethlisberger said, per Fowler. "When you're the best in the world, you want to help participate, you want to win football games. We're all a little frustrated because we're not winning right now."
The Steelers (0-1-1) will hit the road in Week 3 for a Monday night showdown with Ryan Fitzpatrick and the red-hot Tampa Bay Buccaneers as they continue to pursue their first win of the season.