"If there was a blowup or something, I sure as heck didn't see it," Roethlisberger said Tuesday during his weekly radio appearance with 93.7 The Fan in Pittsburgh.
A source said Brown "went off" on a teammate during the week and missed multiple practices and meetings before Sunday's win over the Cincinnati Bengals. Brown also did not show up for Monday's exit meetings.
The Pittsburgh Post-Gazette first reported that Brown threw a football in the direction of a teammate and that Brown was not hurt despite the team listing him on the injury report with a knee issue, making him inactive for the season finale.
A source said Roethlisberger was involved in the incident with Brown, but it was little more than Brown flaring up, as he has in the past.
A source close to the situation told ESPN's Adam Schefter that Brown was upset about being asked to run a hot read again during a walk-through and later told Roethlisberger he felt underappreciated.
Roethlisberger called the magnitude of the story "baffling" based on what really happened. He told the radio show that he talked to Brown on Thursday morning and "everything was great," but he hasn't heard from him since.
Brown was seen around the facility Thursday but wasn't present for that day's practice or Friday's workday.
"Each guy's got to answer that question on their own," Roethlisberger said when asked how the situation will play out in the locker room. "Like I said, I'm blessed to play with him and I consider him one of my closer friends. ... I know guys that are frustrated. I think the biggest thing is, some of the guys that I've talked to, they tried to reach out to him and they haven't heard back."
Roethlisberger said coach Mike Tomlin made the decision "right before the game" that Brown wasn't playing.
Tomlin will address the media Wednesday at noon ET.
Brown enters the third year of a five-year, $72.7 million extension in 2019.
"I hope he's back here with me because he makes me better," Roethlisberger said.