Steelers' Polamalu leaves game

Pittsburgh Steelers safety Troy Polamalu has gone to the locker room with a left knee injury following Cincinnati's opening drive. The team said his return to the game was doubtful.

It was not immediately certain when Polamalu was injured. He was on the field throughout the Bengals' first possession, which ended with Shayne Graham's missed 51-yard field goal attempt.

Polamalu, one of the NFL's top defensive players, was escorted to the locker room by team physician James Bradley, rather than a team trainer — as might be the case with a less-serious problem.

Polamalu missed four games earlier with a torn medial collateral ligament in his left knee before returning Oct. 18 against Cleveland. Polamalu has three interceptions in the four games he's played this season.