PITTSBURGH — Presumed starting quarterback Byron Leftwich apparently tore the medial collateral ligament in his left knee, knocking him out of the lineup as the Steelers' regular season opener draws near.

An MRI taken of the injured knee after he was knocked out of the last preseason game Thursday night reportedly showed the damage, according to Pittsburgh media.

The injury leaves the Steelers with two healthy quarterbacks to choose from to start the regular season — Dennis Dixon or Charlie Batch.

Leftwich's injury came on a pass play early in the second quarter when a falling player landed on the side of his knee.