Pittsburgh, PA (My Sportsbook) - Troy Polamalu's MRI exam revealed the Steelers safety has a strain of the posterior cruciate ligament, Pittsburgh head coach Mike Tomlin said Tuesday at his weekly press conference.

The injury is to his left knee, the same knee that cost him four games earlier this season due to an MCL sprain. Tomlin was quick to point out that the latest injury is not as severe.

"It's a PCL strain as opposed to last time, it was an MCL injury. It happens to be to the same knee, but there is no setback in regards to his MCL," Tomlin said. "We'll let that run its course and see how he feels and listen to the expert advice of our medical staff. We're simply going to take it day-to-day with him."

In regards to the five-time Pro Bowl selection's immediate future, Tomlin labeled Polamalu "questionable at best" for Sunday's game against Kansas City.

Polamalu left this past weekend's 18-12 loss to Cincinnati during the Bengals' first drive of the game and did not return. He made one tackle before leaving, although it wasn't clear if that is where the injury occurred.

In five games this season, Polamalu has three interceptions, 20 tackles and seven passes defended.