In the second quarter, Roethlisberger was sacked by Scott Paxson with under six minutes to play.
He got his leg twisted under him on the sack and was in obvious pain as he grabbed the ankle and put little weight on it as he was helped off the field and into the locker room.
During halftime, x-rays were taken in the locker room and came up negative and he came back out to play for the start of the third quarter.
He appeared to be a bit unsteady as he missed a couple of passes on the first drive of the third, then was picked off with just over seven minutes to play in the fourth.
Joe Haden, who was covering Brown, slipped as the receiver made the catch and Brown was able to race down the sideline, going inside then back out to get around another defender, on a 79-yard score with 2:52 to play and seal the win for the Steelers (10-3).
The win for Pittsburgh, its fourth in a row, moves the club a half-game ahead of Baltimore for the top spot in the division.
The Ravens, who defeated the Steelers twice this season, host the 0-12 Colts on Sunday.