Rapoport: Week 10 game rankings
The wide receiver could miss more time beyond that.
NFL.com and NFL Network's Albert Breer later confirmed the report, per a source who's spoken with the player.
Brown is a consistent performer who emerged last season as a favorite target of Ben Roethlisberger. In eight games this season, Brown has 42 receptions for 499 yards and a touchdown.
Running back Isaac Redman, who rushed for a career-high 147 yards in last week's 24-20 win over the New York Giants, said Saturday he will start in Mendenhall's place. Rookie running back/return specialist Chris Rainey will play despite cracked ribs and running back Jonathan Dwyer -- who missed the Giants game with a right quadriceps injury -- is also expected to play.
The Associated Press contributed to this report