J.D. Martinez re-aggravated a jammed left thumb he’s been dealing with since April on Wednesday afternoon.

The Boston Red Sox slugger was seen after the game with his left hand and thumb wrapped up, per the Boston Herald’s Michael Silverman. The injury initially occurred when the Sox played the New York Yankees in the middle of April, and the slugger re-aggravated the injury on a swing-and-miss during the fifth inning of Boston’s 5-4 win over the Kansas City Royals.

“It’s gotten better, it goes away and then it comes back,” said Martinez, per Silverman. “All it takes is one swing.”

The Red Sox’s training staff has been helping Martinez with the injury by using pads around the injured area. And although Martinez said it helps, he knows it will happen again.

“You’re going to do it when you’re going to do it,” he said.

The designated hitter’s injury isn’t stopping him from producing for the Sox. Martinez is batting .343 with six home runs and 24 RBI so far this season for the Red Sox.

“It’s battle wounds,” Martinez said. “You’ve got to play it through.”

Martinez went 2-for-4 with a two-run home run in Wednesday’s win.