Mets relief pitcher Dellin Betances pitches during the eighth inning...

Mets relief pitcher Dellin Betances pitches during the eighth inning against the Boston Red Sox at Fenway Park in Boston on July 28, 2020. Credit: CJ GUNTHER/EPA-EFE/Shutterstock/CJ GUNTHER/EPA-EFE/Shutterstock

Lifelong New Yorker Dellin Betances is set to stay here for 2021.

The Mets’ righthanded reliever exercised his player option for next season on Sunday. He chose a guaranteed $6.8 million salary over a $3 million buyout and the opportunity to be a free agent.

Heading into the offseason, Betances is a 6-8, 265-pound question mark. He had a 7.71 ERA and 2.06 WHIP in 15 games — and missed three-plus weeks because of a right lat injury — in 2020.

Manager Luis Rojas said in September that Betances had been dealing with that discomfort for about a month before he told Mets decision-makers about it, potentially contributing to his on-field struggles.

Amid all of that, Betances also dealt with the worst velocity of his career. His four-seam fastball averaged 93.6 mph, down from 97.7 in 2018, his most recent full season.

Betances had a 2.36 ERA and was an All-Star four times in five full seasons with the Yankees before joining the Mets.

Reliever Brad Brach also officially picked up his player option, worth $2.075 million, for 2021.

Most of the Mets’ regular relievers are due to return next season, including Betances, Brach, Edwin Diaz, Jeurys Familia, Miguel Castro and Chasen Shreve. Justin Wilson and Jared Hughes are free agents.

Stroman on the clock

The Mets formally extended a qualifying offer to Medford native Marcus Stroman on Sunday. The offer is a one-year contract for $18.9 million; Stroman has 10 days to accept or decline. If he chooses the latter, the Mets will get an extra 2021 draft pick.

Yanks' make qualifying offer to LeMahieu

The Yankees made a qualifying offer to DJ LeMahieu. Others to receive qualifying offers throughout the majors include Trevor Bauer (Reds), Kevin Gausman (Giants), JT Realmuto (Phillies) and George Springer (Astros).

Instructional camp shut down

The Mets decided on Sunday to end their instructional camp two weeks early after two players tested positive for the coronavirus.

Sixty minor-leaguers worked out in Port St. Lucie, Florida, for four weeks without any positive tests. When two cases popped up on Friday, the Mets suspended all activity. Then they decided to end the program completely because it wasn’t worth ramping back up after what would have been at least five days off.