Yankees ace Luis Severino took another step toward making his season debut, throwing off a mound at the Stadium for the first time all year.

Severino – who hasn’t pitched all year due to multiple injuries to his pitching arm and shoulder – tossed in the bullpen Sunday and then threw what he estimated was 15 pitches to batters under the watchful eye of both general manager Brian Cashman and manager Aaron Boone.

“I feel very good; even the (hit off a) change-up that almost hit me. It’s good,” said Severino, buoyed by a positive session and even joking about a line drive sent back at him by assistant hitting coach P.J. Pilittere.

After his prior throwing session, Severino said things actually went better than expected. Sunday was every bit as encouraging.

“Continue to be really encouraged. And you can tell even talking to Sevy just how good he feels,” Boone said. “And this has been building for awhile where he’s I think starting to really gain some confidence in his mind about being sound, being sharp, being healthy, continuing to take these next steps.

“And (Sunday) getting out there and facing hitters for a handful of pitches was big, and I thought overall he looked really sharp. The shape of the slider looks good to me, the ball’s coming out free and easy, so another encouraging step for him.”

After going 19-8 last season with a sterling 3.39 ERA, Severino earned a four-year, $40 million extension in February. But he hasn’t made a single major league appearance since.

The 25-year-old righty suffered soreness in his right rotator cuff before his first outing back in March. Then he had a right lat strain, and has been on a long road back. But he’s convinced Sunday was auspicious.

“Good. I sort of feel pretty good. I haven’t been on the mound this year – the real mound this year – but this is very good,” Severino said. “It feels [like it’s] coming around: The fastball is there, breaking pitches, too. I feel like I’m on the right track.”

The next stop on that track is Tampa. Severino had said before Sunday that he expected his next step would be heading down to Florida for a simulated game, and then on to a minor league rehab stint. This latest session hasn’t seemed to dim that optimism.

“Yeah. I’m very excited about the next. I’m headed to Tampa to throw a sim game there, and then after that…maybe a rehab assignment in High-A or Double-A. We’ll see,” Severino said.

“Larry [Rothschild, pitching coach] told me in the bullpen everything looked good…But I will definitely go to the video room and see how it looks now and in the past and see how it is.”

Unsurprisingly, Boone took a more conservative approach, noncommittal about exactly how Severino’s rehab would proceed.

“No, and I honestly don’t know yet,” Boone said.

“I haven’t even sat with Steve [Donohue, head trainer] and said when did he envision a rehab situation, or how we would do that: Would we do that more through sim games and then go make a start? But he’s certainly moving toward that direction. He and Dellin [Betances] will go to Tampa and continue with their progression.”