Kodai Senga, the New York Mets’ most successful starting pitcher last season, has been shut down indefinitely due to a right-shoulder strain, a team official said Thursday.

David Stearns, the team’s president of baseball operations, told a news conference that the 31-year-old right-hander will be sidelined until symptoms subside after an MRI exam revealed a moderate capsule strain in the back of his shoulder. Senga is expected to start the season on the injured list.

He threw a bullpen on Monday but did not practice Wednesday, when he complained of fatigue in his right arm.

“It’s very frustrating,” Senga said. “To play throughout the season, I’ll take some time off now. I want to prepare to come back as a better player, rather than regret what happened.”

Senga went 12-7 for the Mets with a 2.98 ERA and 202 strikeouts in 166⅓ innings in 2023, his first year in MLB.

He led the team in wins, ERA, strikeouts and innings pitched.

The former Fukuoka SoftBank Hawks ace filed for free agency in 2022 following 11 seasons in Japan.