Cincinnati Reds second baseman Scooter Gennett left Wednesday night's 3-0 victory over the Milwaukee Brewers with left groin tightness, the Reds announced.
Gennett was activated from the injured list last week after recovering from a severe right groin injury suffered during spring training. He is 2-for-19 with a pair of singles in five games.
He flied out and struck out on Wednesday against Jhoulys Chacin, then left the contest an inning later.
Manager David Bell said the team would have a better idea of Gennett's condition on Thursday.
The Reds have sorely missed Gennett, who had 50 homers and 189 RBIs over the past two seasons. He was an All-Star for the first time last year, when he finished second to Milwaukee's Christian Yelich (.326) for the National League batting title at .310.
The Associated Press contributed to this report.