Sean Manaea #59 of the New York Mets walks across...

Sean Manaea #59 of the New York Mets walks across the field before Game Two of the Wild Card Series against the Milwaukee Brewers. Credit: Getty Images

Heading into their new most important game of the season — for what must be the umpteenth time in a month — the Mets’ man on the mound is the one they want there most: Sean Manaea, who emerged over the summer as their best pitcher.

Manaea will start against the Phillies in Game 3 of their NL Division Series a little after 5 p.m. Tuesday at Citi Field. The lefthander will carry with him a 3.47 ERA from the regular season, a strong playoff showing against the Brewers last week and a recent tendency to pitch deep into games.

After that, though? Good luck guessing. The Mets’ bullpen has been unreliable lately, so much so that their most trustworthy reliever may well be David Peterson, a starter.

“It’s a challenge, but, you know, guys will step up,” manager Carlos Mendoza said Sunday night, expressing a sentiment more comforting in June than October. “Not only the high-leverage reliever guys are going to be in the game, and I’m going to ask them to get huge outs. Everybody is going to have to contribute.”

Manaea is a good start, and his presence could help the bullpen. In his final dozen starts before the postseason, he lasted at least 6 2/3 innings in 10 of them.

That was part of a second-half transformation — keyed by a difficult in-season change in arm slot — that turned Manaea into something more than the mid-to-back-end starter he had been most of his career. He finished with a career-best ERA and innings total (181 2/3) and his best WHIP since 2018 (1.08).

“It’s definitely my proudest season I’ve ever had, just from a health standpoint, everything I was able to accomplish,” he said. “It’s been a very fun season for me personally.”

 

As for the bullpen: Diaz has blown saves in two of his past three chances, working across multiple innings in each case. Jose Butto is 1-for-3 in clean postseason appearances and nearly ended the Mets’ season in Milwaukee. Phil Maton, so good since joining the Mets in early July, has had a few hiccups lately. Ryne Stanek has earned his way into Mendoza’s circle of trust.

And then there is Peterson, who has played a key role in two of the Mets’ three playoff wins, picking up the save in the Wild Card Series clincher Thursday and tossing three scoreless innings behind Kodai Senga on Saturday.

Peterson was among the Mets’ better starters — 2.90 ERA, 1.29 WHIP in about two-thirds of a season — but they don’t need him in the rotation for now.

Think of him as a utility pitcher.

“When you get into October, it’s all hands on deck. Just win,” Peterson said. “So like, I start the playoffs in the bullpen and there’s an opportunity for me to eat a couple innings after Senga and there may be an opportunity later for me to go back to starting, maybe bullpen. It’s really just a day-to-day basis, staying in communication, seeing where we’re with how I’m feeling and how everybody else is feeling, what the usage looks like.

“That’s what I told them: Roles at this point, to me, don’t really matter. You could be a starter and you might only go two innings because the manager doesn’t like what he sees.”

Manaea said: “He’s stood up and taken the challenge. He’s definitely a very, very special person to do something like that. It’s not easy. And hats off to him because he’s done an incredible job.”

Pitching plans

The Mets will stick with lefthander Jose Quintana for Game 4 on Wednesday, Mendoza said.

Senga is on track to start Game 5, which will be played Friday in Philadelphia if it is needed. He should be good for about three innings that day after lasting two frames over the weekend in his first outing since July.

“It’s trending in that direction,” Mendoza said. “He’s doing everything that he has to do to continue to feel that way. So progressing well and in a good spot.”

Personnel news

The Mets held an optional workout Monday, a scheduled day off in the NLDS. Most of the pitchers showed up to play catch. Francisco Lindor and backup catcher Luis Torrens were the only on-roster position players present.

Extra bases

Lindor said he still has to complete a 40-minute routine to get his back ready to play each day. He has been playing through an injury since returning to the lineup Sept. 27 (and hasn’t played a home game since Sept. 8) . . . Phillies manager Rob Thomson said third baseman Alec Bohm will be back in the lineup Tuesday after getting benched in Game 2 . . . The Phillies’ Game 3 starter, righthander Aaron Nola, owns a 3.28 ERA and 1.04 WHIP in 14 career starts at Citi Field. “I just always thought it was a beautiful ballpark,” he said. “I always liked coming here. I’m not really sure.” . . . Lindor on Mark Vientos, who hit two home runs Sunday: “Vientos is making himself famous.” . . . Sitting in Luis Severino’s locker was a framed copy of the back page of Newsday from Aug. 18, a day after his shutout of the Marlins. The headline: “Sevsational.”