Dellin Betances of the Mets pitches against the Yankees in Game 1...

Dellin Betances of the Mets pitches against the Yankees in Game 1 of a doubleheader at Yankee Stadium on Friday. Credit: Jim McIsaac

As he struggled to perform as any semblance of his former self, working with greatly diminished fastball velocity and in turn getting far lesser results, Mets righthander Dellin Betances apparently was hurt.

Manager Luis Rojas said Betances, who has been on the injured list with right lat tightness since Aug. 30, revealed to team officials at the time he was sidelined that he had been dealing with a lat issue since he pitched in Boston — one month and one day earlier.

"There are some things he kept from us," Rojas said Monday. "He pitched through it. He didn’t feel anything major. He thought it restricted him from getting out there as far as being consistent with his release point. That’s one of the things he said to us when he went on the IL.

"Those are some of the things he's working on with his arm angle, getting to his release point consistently. Those are some of the things he's working on alongside getting healthy so he can be back for the final stretch."

Rojas said the Mets "hope" he can return before the season ends Sunday. Betances has a 6.10 ERA and 1.65 WHIP in 13 appearances (10 1/3 innings) in his first year with the team — after pitching in just one game for the Yankees n 2019 because of a series of injuries.

For 2021, Betances has a $6 million player option (or $3 million buyout, if he declines the option).

Marisnick done

Jake Marisnick’s regular season ended when he landed on the injured list with right hamstring tightness Monday, a problem that first popped up Sept. 12.

This is the second time this season that Marisnick tried to play through a hamstring issue only to end up on the IL. He also missed a month with a strained left hamstring, which he dealt with during camp in July, though he ended up on the Opening Day roster.

"In a season like this, you gotta push things a little harder than you would in a normal season," Marisnick said. "That’s how I’ve done things my whole career. I’ll take it to the brink, and I think we got to that point where I wasn’t able to do what I’m capable of.

"Part of my game is being able to play 100% and fly around and make things happen on the basepaths. It’s frustrating to me to not be able to do that."

This might end his time with the Mets, too. Marisnick, 29, is slated to be a free agent after the season. He hit .333 with a .606 slugging percentage in 16 games (33 at-bats).

The Mets acquired Marisnick in December from the Astros for two players, including lefthanded reliever Blake Taylor, who as a rookie has a 2.41 ERA in 20 games with Houston.

To replace Marisnick, the Mets called up Guillermo Heredia, who started in centerfield.

Conforto out, too

Michael Conforto was out of the lineup Monday because of left hamstring tightness, the Mets announced. He was considered day-to-day. His availability off the bench was unclear.

Matz, maybe

Such is life for a team on the fringe of contending for MLB’s expanded postseason: The Mets don’t know who will start Wednesday, and they don’t really have any good options.

It is Steven Matz’s turn, but he got rocked for six runs in 2 2/3 innings in his return to the rotation last week. He has a 9.79 ERA.

Other options include long relievers Corey Oswalt and Erasmo Ramirez, plus Ariel Jurado, who is at the alternate training site.

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