Second baseman Freddy Sanchez left Tuesday's game against the Phillies after the third inning when he injured his right knee making a pivot at second base on a double play.
The Pirates scheduled Sanchez for a MRI later in the day.
"Obviously, we don't know what it is," Sanchez said. "But it's nothing big. I'm walking right now. ... As of right now, it feels like a bruise or something."
He said the injury was just part of baseball.
On the play, Sanchez was planting to make a throw to first base as Phillies catcher Rod Barajas barreled toward second. Barajas slid and upended Sanchez, who lay on the ground.
Sanchez Injures Knee