NEW YORK — On the penultimate day of the regular season, the Yankees suddenly have an injury concern in their starting lineup.

Second baseman Jazz Chisholm Jr. exited Saturday’s game against the Orioles after being hit by a pitch on the inside of his left forearm in the bottom of the fifth inning.

Chisholm wasn’t able to get out of the way of the 97-mph sinker from Orioles rookie left-hander Grant Wolfram that ran up and in. He instantly dropped his bat and walked with his head down toward the Yankees’ dugout, waving his arm in pain.

After a brief visit with a Yankees trainer on the top step, Chisholm disappeared down the steps into the Yankees’ clubhouse. Speedster José Caballero jumped off the bench and entered the game in Chisholm’s place, running at first base.

Initial X-rays came back negative, according to the Yankees, although Chisholm will also have a CT scan.

It goes without saying, but losing Chisholm at this stage of the year for any period of time would be a significant blow for this team. The star infielder is having a career year in the middle of the Yankees’ lineup and is already the third player in franchise history to join the 30-homer, 30-steal club in a single season.

This injury scare is another reason for the Yankees to try their best to win the American League East this weekend. They don’t control their destiny, since the Blue Jays hold the tiebreaker, but defending their AL East crown would allow the Yankees to have a bye during the Wild Card Series. That would give Chisholm a few extra days to rest and recuperate ahead of the Division Series next weekend.