Mendenhall's Achilles tightened up on him during Pittsburgh's 26-23 loss last week to the Titans. He made his season debut against the Eagles in Week 5 after recovering from a torn ACL in the final game of the 2011 regular season and has rushed for 74 yards on 19 carries.
Redman was held out of practice all week with a bad ankle. He has carried the ball 50 times for 127 yards and one score in five games this season.
Jonathan Dwyer will get the start at running back for the Steelers, who head into Sunday's contest with a 2-3 mark.
Quarterback Ben Roethlisberger fully participated in practice on Friday after a minor ankle injury in practice on Thursday forced him to miss the last few minutes.
Meanwhile, center Maurkice Pouncey (knee) is questionable.