HOUSTON -- Luis Severino is headed back to New York to have an MRI on his right shoulder, manager Aaron Boone revealed before the opener with the Astros at Minute Maid Park on Monday.

The right-hander “didn’t feel great today,” Boone said, and the Yankees are sending him home to meet with team physician Dr. Chris Ahmad for further evaluation.

“We’re going to get him up to New York and get some answers,” Boone said.

Severino, who has been out since early March with rotator cuff inflammation, threw on flat ground at around 130 feet two days ago, but he has yet to throw off the mound. Monday’s news that he’s suffered another setback is a discouraging sign as he tries to work his way back from the injured list.

“I’m hoping it’s just him not quite being able to get over the hump yet,” Boone said. “The original testing we did with him led us to be pretty confident. We have to make sure he’s right. The fact that he hasn’t been able to graduate from flat-ground throwing to the mound, we have to try to answer those questions as best we can.”

Boone stopped short of saying Severino is in pain; rather, he categorized it as “not as comfortable -- just not quite where it needs to be.”

Severino, who before the injury was slated to resume his position at the top of the rotation, is one of 11 Yankees players currently on the injured list.

More rehab news:

• CC Sabathia, recovering from cardiac surgery, threw 62 pitches in a Minor League rehab outing on Sunday. Boone confirmed that Sabathia is most likely going to join the rotation this weekend, when the team returns home to host the White Sox.

• Dellin Betances threw to hitters on Monday and, if he responds well, will throw a simulated game on Thursday, an off-day for the Yankees.

“If that goes well, he could probably be in a game in [Class A] Tampa by the weekend,” Boone said.

• Giancarlo Stanton, sidelined by a strained left biceps, played catch briefly while the Yankees took batting practice on Monday.