PITTSBURGH — Ben Roethlisberger underwent an MRI exam Tuesday on his injured right shoulder, and the Pittsburgh Steelers won't know if he can play Sunday against the Colts until they get the results.

Roethlisberger, whose throwing shoulder was slightly separated in the first game of the season, was injured on a quarterback sneak near the end of the second quarter of Pittsburgh's 23-6 victory in Washington on Monday night.

Roethlisberger did not play the rest of the game. Byron Leftwich, in first extensive action for the Steelers, replaced Roethlisberger to throw a touchdown pass while leading two TD drives in the second half.

If Roethlisberger can't play, Leftwich would make his first start since last Nov. 18 with Atlanta.

Roethlisberger has started 38 of the Steelers' last 39 games, missing only a season-ending loss at Baltimore last season that didn't affect the team's playoff position.