David Peterson steps up into reliever role for Mets this postseason

In most cases, it’s a demotion — a sign you’ve played yourself out of the brotherhood.

A starter struggles and, having lost his spot in the circle of trust, he’s relegated to the bullpen to work mop-up duty and maybe claw his way back to the rotation.

That’s not what happened in Game 3 of the NL Wild Card Series, though — the one the Mets salvaged from oblivion thanks to Pete Alonso’s storybook ninth-inning home run. No, in this case, it was one of the highest forms of praise. Edwin Diaz gritted his way through 1 2⁄3 scoreless innings, but the Mets still needed three more outs to earn the right to keep playing.

In a weird way, it makes sense that the ball would go to David Peterson.

He’s the second-longest-tenured pitcher on this roster, believe it or not. The Mets drafted him in 2017, and after making his major-league debut in 2020, he became known as the physical representation of untapped potential: He had the height and the pitches and the tools, but aside from a good season in 2022, he hadn’t quite lived up to what people believed to be his talent.

In that way, he was a lot like the Mets themselves: They could have been very good but weren’t, and now are dominating when people least expected it.

Peterson, meanwhile, is a versatile, devastating weapon in an overworked, patchy bullpen that many believe is the team’s biggest weakness.

“It’s been amazing because this is a guy that we saw all season starting games and he’s been able to come to the bullpen, close games, throw multiple innings,” Diaz said. “He’s doing great, man. I’m really happy to have him in the bullpen. It’s another arm we have there and we can use it in any situation. You know, he closed the game in Milwaukee, he threw multiple innings in Philadelphia and he threw multiple innings the other night. He’s just maintained the game right there, and when he gave me the ball, he did a great job.”

There are multiple layers to this. But it probably starts with last offseason when Peterson, coming off one of his worst years in the big leagues, noted that hey, his hip kind of hurt. All the time. It turns out that he had a torn labrum and needed surgery that kept him sidelined until May.

Then May came and, wouldn’t you know it, it’s a lot easier to throw without pain. He was 10-3 with a 2.90 ERA in 21 starts — a pivotal piece for a rotation working without ace Kodai Senga.

Moved to the bullpen ahead of the Wild Card Series, he’s thrown 6 1⁄3 scoreless innings with four hits, three walks and three strikeouts. Above that, very little seems to faze him — after all, this was a guy who was demoted to Triple-A last year and had to at least be wondering about his future in the organization that helped raise him. So right now, he’s just enjoying the ride.

“It’s an honor,” he said after throwing 2 1⁄3 scoreless innings against a fearsome Phillies lineup in NLDS Game 4. “I feel great. Any time I can get the ball and help this team win, especially now at this time of year when we’re in October, we’re fighting for our lives. The postseason, it’s unbelievable. To have this group, the way we go about our business and the way every single guy handles himself, it truly feels like 26 guys are one unit and we’re going out against the rest.”

His contributions also afford Carlos Mendoza the luxury of flexibility heading into their NLCS against the Dodgers. Senga is starting Game 1 and Mendoza hopes to get about three innings out of him. Peterson potentially could come in to be the “bulk” guy behind the Mets’ ace.

He’s a lefty, meaning that Mendoza didn’t have to use a less reliable Danny Young this postseason. Being a lefty and having the potential to pitch multiple innings also could factor into whether Mendoza decides to shed a pitcher to make room for a recuperated Jeff McNeil, who is expected to return from his broken wrist in time for the NLCS. That would allow the Mets to keep a guy like Luisangel Acuna, who brings speed and defense to the mix.

“It’ll continue to be fluid,” Mendoza said of Peterson’s role. “I feel like the job he’s done out of the bullpen has been unbelievable and that’s another weapon that [we can] deploy at any time, at any point of the game — whether it’s in the middle of the game, for a multi-inning role or for a high-leverage situation against a lefty or anybody.

“You know, it’s not easy what he’s done. This is a guy that’s been a starter and then all of a sudden, we clinch the playoffs and we’re asking him to go to the bullpen. He’s been adjusting really well . . . I can see him playing a big role in this next series coming out of the bullpen.”

Pitching coach Jeremy Hefner downplayed the difficulty of moving from starter to reliever. It helps that Peterson has made it look easy.

“He prepared for it,” Hefner said. “He’s treating it similar to a start. He has a very good plan and he goes out and executes that plan. Obviously, in a start, you’re not coming in with runners on base, but you face hitters with runners on base. It’s not that foreign. I think a lot of people make a big deal about coming in with people on base. I don’t think it’s that big of a deal because they face guys with people on base all the time. So try not to make too much of it, he has a plan and goes and executes it.”

Peterson also seems to be loving every second. When he talks about his role, there isn’t a shred of concern about being the odd man out of the rotation. Not when he’s providing so much value elsewhere.

“It means the world,” he said, goggles dripping from the champagne that was sprayed on him after the Mets clinched. “Since getting drafted with this team — it’s the only team I’ve ever been with, they gave me a chance in the big leagues, and to be able to be here for the last five seasons and see what we’ve gone through to get to this point, it’s amazing, and I’m happy and proud of every single guy in this room.”

By Laura Albanese

laura.albanese@newsday.com@AlbaneseLaura

Laura Albanese is a reporter, feature writer and columnist covering local professional sports teams; she began at Newsday in 2007 as an intern.