Below is video of the play that Steelers safety Troy Polamalu may have re-injured his left knee on. Head coach Mike Tomlin said Polamalu was undergoing an MRI exam in his post game press conference following the loss to the Bengals. Polamalu has already missed four games this season with a torn medial collateral ligament in his left knee.
Polamalu apparently was injured while tackling Bengals running back Cedric Benson during Cincinnatis opening possession. Polamalu was observed on the sideline flexing his knee after coming off the field, and he left for the locker room shortly after that with team physician James Bradley.
[flv:http://ll.video.nfl.com/films/s2009/nflcom/w10/091115_phl_polamalu_injury_700k.mp4 480 368]