The Yankees had one of the best bullpens in baseball through the first month of the season, but could be without one of their high-leverage arms for most, if not all, of May.

Darren O’Day was placed on the 10-day injured list Saturday with a right rotator cuff strain and will be shut down for “a few weeks,” manager Aaron Boone said. The 38-year-old sidearmer, who had last thrown on Thursday in Baltimore, has pitched in 10 games this season with a 3.00 ERA and three holds.

“He’s kind of been cranky in the shoulder, really all month,” Boone said. “Started out a little bit early, but able to pitch through it. And then actually the middle of the month was starting to feel pretty good and was kind of a non-issue. Then over the last few days, it still was just in there cranky so decided to get it looked at and found that there was a strain in there.”

The Yankees recalled Mike King from the alternate site to take O’Day’s spot in the bullpen.

O’Day missed more than a month with a right rotator cuff strain in 2016 when he was with the Orioles. Boone said has “dealt with this the last several years.”

“But this is enough to where it does require a few-week shutdown and hopefully with that, he can get this thing right and still be an important part of our bullpen moving forward,” Boone said.

O’Day became the second key Yankees reliever to hit the injured list this season, joining Zack Britton (elbow), who is on the 60-day IL. Britton threw 15 pitches off the mound Friday and remains on track to return by the beginning of June.

Aaron Hicks was hit by a pitch in the right foot in the sixth inning and appeared to be in a lot of pain. After a slow walk to first base, he remained in the game the rest of the way.

“He was good enough to stay in the game,” Boone said. “Hoping he’s all right.”

Giancarlo Stanton, the Yankees’ hottest hitter with three straight three-hit games, was out of Saturday’s game after playing eight consecutive. Boone said he wanted to rest Stanton on Thursday afternoon in Baltimore, but with Aaron Judge out of the lineup, held off until Saturday.

“Just a day game after the night game in a pretty long stretch here, just trying to play a little bit of the long game here as well,” Boone said. “I think he was on board with that during this stretch.”

Gio Urshela, who had been carrying another hot bat, also got the day off.

Luis Severino, continuing to rehab from Tommy John surgery with an expected return this summer, is scheduled to face live hitters for the first time on May 10 or 11, Boone said. On Thursday, Severino pitched with hitters in the box, throwing 20 pitches, sitting down and then coming back for 15 more, throwing all of his pitches.

Gary Sanchez allowed his first passed ball of the season in the sixth inning.