BALTIMORE — José Caballero’s hopes of remaining the Yankees starting shortstop hinge on a Tuesday morning MRI.

For now, a right middle finger injury was enough to keep Caballero out of the Yankees lineup for Monday’s series opener against the Orioles at Camden Yards, sustained while diving back into first base in the ninth inning of Sunday’s loss to the Brewers.

After Monday’s game, Caballero will travel to New York to undergo an MRI and see team physician Dr. Christopher Ahmad and a hand specialist to determine the severity.

“I don’t think it’s a fracture,” Caballero said before pinch-running in the ninth inning and getting thrown out trying to steal second to end a 3-2 loss. “Not worried [about going on the injured list]. I’m just not happy that I have to be out of the lineup today.”

But Aaron Boone, who generally downplays any worries about potential injuries, sounded more concerned than Caballero.

“There’s definitely some concern because Cabby, he’s as tough as they come,” Boone said. “Just had a little hard time when he went to throw today. The good thing is hitting was good. So we’ll see. He’s going to get some tests [Tuesday] morning. See what we have over the next day or two.”

Max Schuemann started at shortstop Monday night, and Boone indicated he would be comfortable with him (and perhaps Ryan McMahon in spot duty) filling the void if Caballero just needs a few days.

If Caballero has to go on the injured list, the recently demoted Anthony Volpe and Oswaldo Cabrera would be candidates for a call-up from Triple-A.

But first comes the MRI for Caballero, whose strong play on both sides of the ball over the first month-plus of the season forced the Yankees to change their plans for Volpe, whom they initially planned to reinsert at shortstop once he came off the IL last week.

“[Caballero] has been great,” Boone said. “He’s been such a good performer for us here to start the year, on both sides of the ball. He’s been a key part of our team to this point, but again, hopefully it’s just a day-to-day situation. We’ll have a better idea of that [Tuesday].”

Caballero dodged an injury concern last week after he was hit on the left elbow by a pitch, needing only a day out of the lineup Thursday to deal with some swelling before playing all three games over the weekend in Milwaukee.

He is still wearing tape on that left elbow Monday, but now has his right middle finger taped up as well.

The speedy Caballero was trying to steal second base in the ninth inning of a tie game Sunday when he dove back into first base, and while he was wearing a sliding glove on his right hand, it did not fully protect him.

“Didn’t work,” he said. “It’s just the part that is covering that part of the finger, it’s kind of soft, so it doesn’t really help much.”

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And so the shortstop with a 1.6 bWAR — the fifth-highest mark on the Yankees entering Monday — was put on hold.

If Caballero does need to go on the IL, it would set up an interesting decision for the Yankees.

Volpe did not exactly set the world on fire in his first week at Triple-A following his activation off the IL and demotion to Scranton/Wilkes-Barre.

In five games, he hit 4-for-24 (.167) with a .472 OPS.

Cabrera, who offers more positional flexibility, had a rough start to the season but has hit better of late, going 14-for-36 (.389) with a 1.032 OPS over his last nine games.

Boone said he had not spoken to Volpe since giving him the news last Sunday that he was being optioned to Triple-A, but has maintained that the 25-year-old is equipped to handle it well.

“Definitely it’s challenging to deal with that, but everyone has challenges they’ve got to deal with and some adversity they’ve got to deal with,” Boone said. “He’s mentally a very tough kid and that’ll serve him well as he navigates this.”