NEW YORK — Orion Kerkering’s difficult stretch has reached a new point.

According to Todd Zolecki of MLB.com, the Phillies are optioning the 25-year-old reliever to Triple-A Lehigh Valley.

The move comes after interim manager Don Mattingly expressed a “pretty high degree of worry” about Kerkering following another difficult outing in the Phillies’ 10-3 loss to the Mets on Saturday.

Kerkering allowed four earned runs on four hits and two walks in the eighth inning Saturday. A night earlier, Juan Soto took him deep for a three-run homer with two outs.

That’s seven earned runs across two appearances in Queens. Kerkering has a 15.43 ERA over his last seven outings and a 10.29 ERA over his last 15.

“It seems to be spiraling a little bit,” Mattingly said.

The Phillies used Kerkering with a three-run deficit because Mattingly wanted to stay away from his highest-leverage options while still keeping the game within reach.

By the end of the inning, Mattingly acknowledged even finding those types of spots for Kerkering had become difficult.

“You have to be able to use him there,” Mattingly said. “In a game like that, I’m not going to try to chase a three-run deficit in that inning.

“It’s hard to find any places to use him.”

Kerkering has dealt with turf toe this season, but said Friday that the toe was not responsible for his recent struggles.

Instead, he pointed toward a combination of mechanics, execution and an inconsistent sweeper.

“Just rough last couple months,” Kerkering said.

The sweeper has been his signature pitch since he raced through the Phillies’ farm system and reached the majors in 2023. Kerkering acknowledged Friday that hitters know what’s coming more often now.

“It has been inconsistent,” Kerkering said. “They’re just throwing it a lot. I think maybe a factor of guys sitting on it more. It’s been my bread and butter. If guys didn’t know, they probably know right now that’s my pitch.”

Mattingly also wondered whether confidence had become part of the equation.

“I think confidence probably as much as anything,” he said before Saturday’s game.

The Phillies could use the old version of Kerkering badly right now.

Jonathan Bowlan is day to day with right groin tightness, though the injury has not resulted in an injured-list stint. The Phillies are already without Jesús Luzardo, and their middle relief has been a problem throughout the season.

Phillies relievers from the fifth through seventh innings have combined for a 5.26 ERA, the worst mark in the majors.

Jhoan Duran has been excellent at the back end, carrying a 1.76 ERA with 32 saves, but getting a lead to him has too often been the problem.

Mattingly said Saturday that keeping games close through the middle innings has been a “trouble spot.”

“We haven’t been able to keep the game in check in that middle,” he said.

The Phillies have not officially announced Kerkering’s option or a corresponding move.

One name worth watching is Nestor Cortes.

Cortes threw three scoreless innings for Triple-A Lehigh Valley on Saturday, striking out three without issuing a walk as the Phillies continue to build him up.

Mattingly said before Saturday’s game that Cortes is moving toward a point where he could potentially contribute in the majors.

“He’s building,” Mattingly said. “He’s heading in the direction that that’s possible, that we might be able to use him.”

Cortes is also eligible for the postseason.

With seven games remaining, the Phillies are still trying to determine which arms they can trust to connect their starting pitching to the back of the bullpen.

For now, Kerkering will try to work his way back into that group from Lehigh Valley.