Dellin Betances worked all the way back for eight pitches.

After rehabbing a right shoulder impingement and a strained lat for 5 ½ months just to make his 2019 debut Sunday in Toronto, the Yankees reliever is now out for the year with a partially torn left Achilles tendon.

“Obviously, heartbroken for Dellin and knowing he worked so hard to get to this point to be a factor for us and have him successfully debut for us. Now this,” manager Aaron Boone said Tuesday night after the Yankees announced the news following an 8-0 win over the Angels.

The injury is believed to have happened when Betances jumped on the mound after recording his second strikeout in as many batters against the Blue Jays. Boone said he “came down a little awkwardly,” but didn’t say anything at the time.

Betances reported to Yankee Stadium on Tuesday feeling sore, at which point he underwent tests and imaging that revealed the brutal diagnosis for the pitcher who is about to enter free agency.

“It made me nauseous when I was thinking about it,” said reliever Zack Britton, who suffered a ruptured Achilles in 2017 and spent time Tuesday speaking with Betances about his own injury. “Tough for him, with everything he’s done this year to get back to us. That was tough to talk to him about it.”

Betances was seen Tuesday by Dr. Justin Greisberg at New York Presbyterian and will receive a second opinion from Dr. Martin O’Malley at the Hospital for Special Surgery. Though surgery has not been ruled out, Betances will be treated conservatively for now.

The 31-year-old Brooklyn product had been one of the Yankees’ most dangerous arms before this season, with a powerful fastball and sharp breaking ball. The Yankees hoped his return would bolster an already strong bullpen in time for the postseason. It was the idea of pitching in the playoffs that had kept Betances going during his rehab, but now he will have to watch from afar again.

“Just sad, man,” said Luis Severino, who made his own season debut Tuesday. “He’s been working hard to get back here. He was so happy in Toronto when he pitched that game. It’s hard to see.”