The good health of the Yankees’ starting rotation lasted 87 games.

Then Luis Severino walked off the mound after throwing one warmup pitch before the third inning of Game 88.

On a night when his velocity was down and he surrendered back-to-back-to-back home runs, Severino exited with right shoulder tightness in what became a 7-6, 10-inning win over the Reds on Wednesday night in The Bronx. Severino was examined by team physician Dr. Christopher Ahmad and will undergo an MRI exam on Thursday.

“After that second inning, when I was warming up, it was getting worse,” Severino said. “So I told myself before something even bigger happens, let me stop it right here. Hopefully it’s not something that would take much time.”

The right-hander said based on the way he felt after the game, he was not too concerned about the injury, but the MRI will have the final say.

Severino, who has a lengthy injury history, including Tommy John surgery in 2020, was visited by manager Aaron Boone and a trainer with no outs in the second inning after he allowed consecutive homers to the bottom three hitters in the Reds lineup. The last of those home runs came on a 92 mph fastball, as Severino’s four-seamer averaged 94.1 mph on Wednesday — a drop from his season average of 96.1 mph.

“I just wanted to go out because the stuff hadn’t ticked up yet,” said Boone, who noticed Severino’s drop in velocity from the first inning. “I was just trying to get a read on him and look him in the eye and see where he was at.”

The right-hander stayed in the game to retire the next three batters, including a strikeout of Brandon Drury with a 96 mph fastball.

But after Severino took the mound to start the top of the third inning, he threw just one warm-up pitch before reversing course and walking off the field, ending his night early.

“In the [second] inning, I was trying to throw anything that I got in my arm,” Severino said. “I think maybe because of that, the next inning I was not feeling that great. So I feel like if I go another inning and push it harder, it’s going to be even worse.”

Severino said he woke up on Wednesday with his shoulder feeling a little tight, but thought it would loosen up as he went through his pregame routine and threw in the bullpen. Instead, it just got tighter inning by inning.

“When I talked to him after the first inning, he was just a little leery of letting it go,” Boone said. “But he kept saying, ‘I feel really good.’ Something was telling him to hold back a little bit. Sometimes he can be that way a little bit early where he’ll ease into it a little bit. I think in his mind, with his injury history, he gets a little cautious.”

Since signing a four-year, $40 million extension in 2019, Severino has thrown just 104 innings — 86 of them this season. In 2019, Severino dealt with rotator cuff inflammation before a subsequent lat strain knocked him out for most of the season. He then had Tommy John surgery in February 2020, and his comeback to the Yankees was delayed in 2021 by a groin strain and then shoulder tightness.

Still, Severino had remained healthy this season and the Yankees’ regular five pitchers started 84 of their first 88 games. The Yankees have monitored Severino’s workload after he came into the year having pitched just 18 innings over the last three seasons combined.

While Severino was hopeful he could make his next start, which wouldn’t come until after the All-Star break, the Yankees have internal options if he is forced to miss time — led by JP Sears, who relieved Severino with 3 ²/₃ innings Wednesday, Clarke Schmidt and Domingo German.

“Kind of hope for the best [Thursday], but at least on exam, there was no alarming things,” Boone said. “But that’s getting ahead of ourselves.”