David Peterson has disastrous outing in return to Mets’ rotation

The left-hander allowed seven runs — all earned — in just 3 ²/₃ innings in Wednesday’s 14-2 loss to the Nationals at Citi Field.

And because the state of their pitching staff is so bad, Peterson will almost certainly remain either in the rotation or used behind an opener the next time through the rotation.

“He’s a big part of this team,’’ Carlos Mendoza said.

Peterson said his issues stemmed from falling behind in counts.

He also walked three batters, but insisted he could right himself.

“I’ve done it before,’’ Peterson said. “And I believe in myself and I know I have the stuff to do it.”

Mendoza also expressed belief that Peterson has the ability to be effective.

“We’ve seen flashes of it,’’ Mendoza said. “He’s got more than enough to compete in the strike zone.”

David Peterson wears a dejected expression during the fourth inning of the Mets’ 14-2 loss to the Nationals on April 29, 2026 at Citi Field. Jason Szenes for New York Post

Peterson’s ERA in five starts this season is 8.10, compared to his success out of the bullpen, where he’s allowed one run in seven innings in two appearances.

And he’s also allowed six earned runs in the first inning of his five starts.

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“Out of the bullpen in his last couple of outings, he comes in aggressive and attacking,’’ Mendoza said. “He uses all his pitches and is competing in the strike zone.”

In the rotation, though, it’s a different story, but with so many pitchers struggling, the Mets have little choice but to keep going to the lefty.

David Peterson looks on from the bench after being taken out in the fourth inning of the Mets’ blowout loss to the Nationals. Jason Szenes for New York Post

Sean Manaea was as bad in relief as Peterson, allowing six runs in 2 ²/₃ innings.

Luis Robert Jr. remained sidelined by lower back tightness.

The center fielder had an MRI exam Wednesday, and Mendoza said they were awaiting the results following the latest loss.

The Mets have limited Robert’s playing time in an attempt to prevent the injuries that have plagued him the previous two seasons.

It’s not off to a great start.

“[His back] didn’t improve much after treatment,” Mendoza said before the game. “We’re doing everything in our power to keep him on the field.”

With Robert out and Juan Soto limited to DH duties as he deals with left forearm tightness, the Mets are willing to take advantage of Carson Benge’s ability to play all three outfield spots.

Soto, who went 3-for-5 with a solo homer in the Mets’ loss on Wednesday, entered the day swinging at the highest percentage of pitches outside the strike zone of his career (23.1 percent).

Juan Soto rips a solo homer in the third inning of the Mets’ blowout loss to the Nationals. Jason Szenes for New York Post

His career mark is a more selective 17 percent.

With Francisco Lindor out and much of the rest of the offense not hitting, Mendoza was asked if opposing teams will avoid giving Soto good pitches.

“Regardless of who’s in the lineup, a lot of teams pitch around him,’’ the manager said. “I feel like he continues to get, maybe not as many, [but] pitches to hit. If not, he’s got to trust his teammates.”

Francisco Alvarez went 0-for-4 with three strikeouts and is now hitless in his last 12 at-bats, with Mendoza saying the catcher is “in-between” in his at-bats.

A. J. Minter, rehabbing from last year’s lat surgery, is expected to pitch in two more minor league rehab games Friday and Sunday.

If all goes well, Mendoza didn’t rule out the possibility of the left-hander being activated at some point next week.

“We’ll see,’’ the manager said. “We said we’d take it slowly.”

Tommy Pham, designated for assignment by the Mets, cleared waivers and elected free agency. The veteran outfielder went 0-for-13 in his second stint in Queens.

He was replaced on the roster by another right-handed hitting outfielder, Austin Slater.

The Mets signed shortstop Jamari Baylor to a minor league deal.

The 25-year-old spent last season in the independent Atlantic League and has never played above High-A in the minors after being selected in the third round in 2019 by the Phillies.