Emilio Bonifacio left Thursday's game in Pittsburgh after injuring himself in the first inning.
Bonifacio grounded the game's second pitch to shortstop and collapsed when he turned to run out of the batter's box. He remained on the ground for some time before needing assistance to leave the field.
Junior Lake moved from left field to center field in place of Bonifacio, with Chris Coghlan replacing Bonifacio in the batting order and coming in to play left field.
It was reported later in the game that Bonifacio suffered a right rib cage injury and will be reevaluated Friday.
Bonifacio is batting .266 with a .311 on-base percentage this season. He's scored 29 runs with 10 doubles, 13 stolen bases and 16 RBIs.