PHOENIX — Add another concern to the Yankees’ already hefty list of them heading into the final week of the regular season.

Clarke Schmidt, who returned from Tommy John surgery on Wednesday, was warming up Sunday to make his second appearance before experiencing cramping in his right biceps, which ultimately kept him out of the Yankees’ 8-4 loss to the Diamondbacks at Chase Field.

“Nothing structural, it was more precautionary,” Schmidt said. “Obviously given the circumstance, coming back from surgery, I don’t want to push through anything. All the testing was fine, nothing with the shoulder, nothing with the elbow. It was more a cramping-type feeling. I had nothing in catch play earlier today and in the previous days I’ve been feeling very strong. So just very, very minor, just precautionary.”

New York Yankees relief pitcher Clarke Schmidt delivers during the seventh inning of a baseball game against the Minnesota Twins, Wednesday, Sept. 16, 2026, in Minneapolis. AP Photo/Abbie Parr

Schmidt was expected to see the Yankees’ team doctor when they returned home, but no tests were planned as of Sunday.

Even if Schmidt checks out fine, it is a reminder of the tightrope the Yankees are walking in hoping the former starter can be part of their playoff bullpen just 14 months removed from major surgery.

After making his season debut on Wednesday, Schmidt warmed up in Saturday night’s game before Aaron Boone went to Michael Fulmer, who served up a walk-off home run in the bottom of the ninth inning.

Schmidt was then warming in the bullpen again in the top of the sixth Sunday before the biceps issue popped up, leading to Tim Hill throwing the bottom of the frame instead.

“I’m hoping it’s not a big deal, but enough to have him not go into the game,” Boone said. “We’ll see what we have there.”