Gennett also left Saturday's game in Washington with the same tightness. There was no immediate word as to the severity of the injury.
Against the Reds, he made a play on a grounder that was deflected by starting pitcher Jimmy Nelson to end the fourth inning. His turn in the batting order didn't come up in the bottom half of the inning and he was replaced by Rickie Weeks at top of the fifth.
Gennett was 0 for 2 in the game. He is batting .305 with eight home runs and 34 RBI in 89 games.