NEW YORK -- When Mets manager Carlos Mendoza called upon Edwin Díaz in the seventh inning of National League Wild Card Series Game 3 last week, the closer was shaky, walking two of the first three batters he faced before recovering to escape a jam. Back in the dugout between innings, various Mets approached Díaz and advised him to trust his stuff.

Six days later, in the ninth inning of NL Division Series Game 4, Díaz was once again wild, throwing eight of his first 10 pitches outside the strike zone. During a mound meeting, pitching coach Jeremy Hefner and shortstop Francisco Lindor both implored Díaz to throw his fastball right down the middle.

“They said, ‘Your ball’s got good life today. Your fastball is looking good,’” Díaz recalled. “I was trying to hit the corners with my fastball. That’s why I got behind the hitters. As soon as they told me that, I said, ‘OK, I will do this.’ I started doing that, and my inning was better.”

On both occasions, Díaz recovered to give the Mets crucial late outs in a playoff clincher. At his best, Díaz remains an overpowering pitcher, with a fastball as hot as 101 mph and a slider that’s nearly unhittable when located well.

But this postseason, Díaz has frequently not been at his best. Through three appearances, he’s walked five of the 17 batters he’s faced. He blew a save in the eighth inning of NLDS Game 2 in Philadelphia, allowing three runs on two hits and a walk. He hasn’t had a clean appearance in three weeks.

That’s a problem for the Mets, who intend to rely on Díaz as much as possible in their biggest games of the season, including the NL Championship Series beginning Sunday.

“In order for us to continue to get where we want to get, we’re going to need him,” manager Carlos Mendoza said. “I’ve been saying that since May, when he was struggling. And he always finds a way to get the job done, to go through those struggles.”

Any conversation about Díaz’s issues tends to be relative in nature. Díaz was certainly a successful pitcher in his first year back from major knee surgery, producing a 3.52 ERA in 54 appearances and striking out 14.1 batters per nine innings. That latter figure is elite; among pitchers with as many innings as Díaz, only Fernando Cruz, Mason Miller and Aroldis Chapman punched out batters at a higher clip.

But when compared to what Díaz accomplished before his surgery in 2022, his stat line loses some of its luster. That year, he was the best reliever in baseball, bar none, with a Major League-leading strikeout rate and expected ERA. He only blew three saves in 35 chances, compared to eight in 29 tries this year (including the playoffs). It’s been a somewhat jarring fall for Díaz, because it’s not as if his stuff is clearly worse. He still features the same elite fastball-slider combo he always has.

“When you get knocked down a couple times,” Mets outfielder Brandon Nimmo said, “it takes a little bit of adjustment and then confidence of doing it and throwing it in the zone and finding that success in order to get that confidence back again.”

“I think there’s a combination of a lot of things here in the past week, where we’ve been riding him pretty hard,” added Mendoza. “But the one thing from him is he always wants the baseball. He wants to be in those situations. He wants to be in those moments, and he’s our guy.”

Recent workload could indeed be a factor for Díaz, who threw 153 pitches over an 11-day period from Sept. 29 through Oct. 9. While that may not sound like much, it’s far outside the bounds of typical usage for Díaz, who piled up four of his seven highest pitch counts of the year during that stretch.

If workload has been the primary issue, Díaz should benefit from the three full days of rest he’ll receive between the NLDS and NLCS. And if it’s simply a matter of confidence, then Díaz claims he’s already learned his lesson.

“That’s something I’ve got to have in mind always,” Díaz said. “Go after hitters, throw my stuff, and I will be fine.”