Seattle Mariners slugger Josh Naylor exited Thursday's game against the visiting Chicago White Sox after he was seen grimacing during his at-bat in the third inning.

Naylor first showed signs of discomfort during his first plate appearance in the second, which ended in a strikeout.

In the third inning, he continued to exhibit pain as he fouled off a pitch and then swung at and missed a changeup. He ultimately grounded out to second to end the inning and was replaced at first base by Donovan Solano with Seattle leading 2-0.

There was no clear indication what injury Naylor may have suffered, nor was word given by the team at the time of his departure. Last year, Naylor missed a month during the second half of the season with a right oblique strain.

Since joining Seattle on July 25, Naylor has hit .261 with three home runs and six RBIs in 13 games. He has also gone 10-for-10 in stolen bases. Overall this season, which includes 93 games with the Arizona Diamondbacks, Naylor has batted .289 with 14 homers and 65 RBIs.