TAMPA — Two MRI exams and a CT scan during the offseason didn’t find the reason why Luis Severino’s right forearm was sore after he throws changeups and forced him to be shut down Thursday.

So after being examined by Yankees doctor Chris Ahmad on Friday morning, Severino was making plans to fly to New York and begin three days of testing at Columbia-Presbyterian Hospital on Monday.

“Going through a battery of tests. We will go through some of the ones we already have, but go through a number more to try to get to the bottom of what’s going on because it is a bit of an unknown for us right now,’’ Aaron Boone said following the final full-squad workout at Steinbrenner Field on Friday. The Yankees open the exhibition schedule Saturday at home against the Blue Jays.

The need for extensive testing be done on the 26-year-old right-hander stems from previous tests not delivering a reason for the soreness.

“Some of the tests, the MRIs and stuff that he has had already done, all kind of suggest he is OK, so we have continue to explore and find out what’s giving him that discomfort,’’ Boone said.

Severino said several reasons for the soreness have been deleted, but the search continues.

“We have (taken) a couple of issues (off) the board. Like shoulder and stuff like muscles, but we’ll see Monday what the real issues are,’’ Severino said.

After Ahmad examined Severino, the pitcher said he didn’t get a diagnosis.

Luis Severino
Luis SeverinoCharles Wenzelberg/New York Post

“We’re looking for the all the answers. It could be a nerve, a muscle a bone. We will do (tests) up there to see what the real issue is,’’ Severino said.

With the discomfort in the forearm below the elbow, Severino doesn’t believe the cause is related to the hinge. Nor does he think a serious issue is lurking.

“I don’t think there is something wrong. The way I feel, I could go out there (Saturday) and play catch,’’ said Severino, who didn’t feel the soreness after throwing fastballs and sliders. “When I did the tests it showed nothing.’’

It is the second consecutive spring training Severino, 26, has been sidelined. A year ago, he was diagnosed with an inflamed right rotator cuff. While rehabbing that injury, Severino strained a lat muscle. Those problems resulted in Severino making just three September starts and two in the postseason. Despite feeling soreness after Game 3 of the ALCS against the Astros, who copped a 4-1 win, Severino checked out fine and would have been Boone’s Game 7 starter had the Yankees forced a winner-goes-to-the-World Series finale.

“It’s strange to hear this stuff again,’’ Severino said. “We’re dealing with it and seeing what we can do.’’

With the season beginning March 26 against the Orioles in Baltimore, there is enough time for Severino to be ready and be in the rotation if the problem isn’t serious. However, until the cause for the soreness is discovered, there is a concern. Boone didn’t want to get into speculation about Severino not being healthy enough at the start of the season.

Puzzling to Severino is that it is only the changeup that produces the soreness and it doesn’t surface after he throws fastballs and sliders.

“It’s below the elbow where the muscle touches the bone, a weird spot,’’ Severino said. “I feel like after you throw nine innings. Later on (soreness) goes away. (Friday) I feel way better than (Thursday).”

When discussing Severino’s situation, GM Brian Cashman and Boone mentioned there was a loose body in the arm that didn’t cause problems thus didn’t need to be surgically removed. Asked about that Friday, Severino said he didn’t believe that was related to the soreness.

“They told me that was not the issue,’’ Severino said. “If it was the issue, I couldn’t throw my fastball. Ninety percent of pitchers have this thing. For me, it is not an issue.’’

After last season, the first of a four-year deal for $40 million, Severino was asked if he is frustrated.

“I just want to pitch. I’m doing all the things they want me to do in the offseason to come here healthy. I felt good until (Thursday). I was watching TV and something wasn’t right. It is stuff that happens and you have to deal with it,’’ Severino said.

Should Severino join James Paxton (back surgery) and be unable to start the season, the Yankees would be looking for two rotation replacements from the group of Jordan Montgomery, Mike King, Luis Cessa and Deivi Garcia.