J.D. Martinez leaves with back spasms

KANSAS CITY -- Red Sox slugger J.D. Martinez left Thursday's 7-5 win against the Royals with back spasms in the top of the fifth inning.

With a runner at first and nobody out, Sam Travis pinch-hit for Martinez, who had doubled and flied to center in his previous two at-bats.

Manager Alex Cora said Martinez felt something in his back when he was on base in the third and turned to judge the flight of a ball hit by Rafael Devers. It marked the third time since late April that Martinez has missed a game or left a game with back spasms.

"It's probably going to be a tough flight for him, but we'll know a little more [Friday]," Cora said. "He turned to see the flight of the ball and felt it. Hopefully, it's nothing and he'll be able to play during the weekend."

Martinez is hitting .296 with 12 homers and 33 RBIs.