CLEVELAND -- The Yankees added right-hander Mark Leiter Jr. to their bullpen for Game 4 of the American League Championship Series, replacing right-hander Ian Hamilton as an injury substitution.

Hamilton sustained a left calf strain while covering first base during the sixth inning of New York’s 7-5, 10-inning loss to the Guardians in ALCS Game 3 on Thursday night.

Major League Baseball approved the roster substitution after Dr. Gary Green, MLB’s medical director, confirmed the injury following a full review of the medical information.

In accordance with the rules, Hamilton will be ineligible to return for the World Series, should the Yankees advance.

Leiter, 33, was acquired by the Yankees from the Cubs on July 30 ahead of the Trade Deadline, but he struggled in 21 appearances, posting a 2-1 record and a 4.98 ERA. He was not included on the club’s AL Division Series roster against the Royals.

Overall this season, Leiter was 4-5 with a 4.50 ERA in 60 appearances.

“Hopefully, when called upon, he’ll give us quality outs,” general manager Brian Cashman said. “He’s had a hell of a year, just not as good when he got here for us. But he’s certainly capable. He’s a pretty good weapon against left-handed hitters.”

Clayton Beeter and Cody Poteet were also discussed, but Cashman said the Yankees chose Leiter because of that track record against lefties and Cleveland’s roster construction.

Cashman said that left-hander Nestor Cortes was not considered to replace Hamilton, as “we’d be skipping too many return-to-play protocols to put him in there and safely deploy him.”

Cortes, who is rehabbing from a left elbow flexor strain, hopes to be ready to pitch in a potential World Series.

“There are a few more hurdles for him to climb to put him in a safe zone,” Cashman said. “It’s his career we’re talking about. We’ll make sure he’s right.”

Hamilton was a reliable contributor to the Yankees' bullpen this season, posting a 3.82 ERA across 35 appearances, though he did not pitch in the Majors from June 16 until Sept. 9 due to a right lat strain.