NEW YORK -- Internally, the Mets believed they boasted a fine bullpen even before their addition of Dellin Betances. That the team made no major changes to a relief corps ranked 26th in the Majors in bullpen ERA last season, the Mets thought, hid the fact that their pitchers largely underperformed their 2019 projections.

Still, while the Mets were counting on improvement, they knew it was not the type they could sell to a fan base seeking change. That type showed up to Citi Field on Thursday fresh off eight seasons in the Bronx. He slipped a pinstriped Mets jersey over his shoulders and talked about how excited he is to move from one borough to the next.

Betances’ new general manager, Brodie Van Wagenen, used his new arm's presence as evidence that the Mets can feature not just a better bullpen, but “one of the best bullpens in baseball.”

“This signing,” Van Wagenen said, “was intended to blow the cover off of our ceiling.”

Coming to the Mets on a one-year, $10.5 million contract that includes player and vesting options for the 2021 and ‘22 seasons, Betances is a reliever who has “size … strength and … swagger when he takes the mound,” in Van Wagenen’s words. He used those attributes to strike out 100-plus batters for five consecutive seasons with the Yankees, posting the fourth-highest career strikeout rate -- 14.6 per nine innings -- in Major League history.

That Betances was available on a one-year guarantee was due to the fact he missed more than five months of last season due to a shoulder injury, then partially tore his left Achilles tendon stepping off the mound in his first game back. As early as November and the official start of free agency, the Mets expressed interest in Betances, doing their due diligence on his health and rehab. (Betances has begun a throwing program, with the expectation of being at full strength by the start of Spring Training.)

Signing Betances required “creativity” in contract negotiations, according to Van Wagenen, who attempted to offer him financial upside while also protecting the Mets’ interests.

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The rest sold itself. Although Betances grew up a Yankees fan in Manhattan’s Washington Heights and Lower East Side neighborhoods, he held plenty of respect for Mets including Pedro Martinez, Edgardo Alfonzo, Rey Ordonez, Al Leiter, Jose Reyes and Carlos Beltrán. The last player mentioned is now the Mets’ manager, familiar with Betances from their three-year run as Yankees teammates. During Betances’ free agency, both Beltrán and another former Yankees teammate, Robinson Canó, reached out to try to sell him on the Mets.

“The Mets were the team that wanted me from the start,” Betances said.

They wanted him because of what he can mean to their bullpen. In Flushing, Betances joins Edwin Díaz, Seth Lugo, Jeurys Familia, Justin Wilson, Brad Brach and Robert Gsellman in the Mets’ bullpen core. That group contains plenty of upside, but also lots of risk. Betances has recorded a total of two outs in the last year. Díaz and Familia are coming off hugely disappointing seasons, making them focal points of the Mets’ offseason strength, conditioning and health programs.

At their best, those pitchers can be -- and have been -- dynamic. With Betances among them, the Mets are holding out hope for just that.

“We knew that we had potential in our bullpen even with the existing guys that we had,” Van Wagenen said. “We’re excited about what the potential is, and now it’s just a matter of having everybody come together and perform the way they’re capable.”