WEST SACRAMENTO, Calif. — New York Yankees pitcher Marcus Stroman had a setback as he tries to return from a left knee injury that has sidelined him for the past month.

Manager Aaron Boone said Sunday that Stroman still had “discomfort” in the knee after throwing a live batting practice session in Tampa, Florida, on Friday and will be reevaluated before the team figures out the next step in his rehabilitation process.

“He’s gotten a lot of treatments on it and stuff,” Boone said. “It just can’t kind of get over that final hump to really allow him to get to that next level on the mound. We’ll try and continue to get our arms around it and try and make sure we get that out of there.”

Stroman hasn’t pitched since allowing five runs in two-thirds of an inning against the San Francisco Giants on April 11. He was placed on the 15-day injured list the next day with what Boone hoped at the time would be a short-term absence.

But there is no timeline for the right-hander’s return, and Boone said the injury likely impacted the way Stroman pitched before going on the IL. He was 0-1 with an 11.57 ERA in three starts.

“Certainly that last start, I think he just couldn’t really step on that front side like he needed to,” Boone said. “I talk about how these guys are like race cars, and one little thing off and it can affect just that last level of command or that last level of extra stuff that you need. So we’ll continue to try to get him where we need to.”

Stroman had surgery March 19, 2015, to repair a torn ACL in his left knee. He returned to a major league mound that Sept. 12.

Stroman, 34, is in the second season of a two-year contract guaranteeing $37 million. His deal includes a $16 million conditional player option for 2026 that could be exercised if he pitches in at least 140 innings this year.

Last season, Stroman was 10-9 with a 4.31 ERA in 30 games (29 starts) when he threw 154⅔ innings, his most since 2021 with the Mets. Stroman struggled in the second half and did not pitch in the postseason, when the Yankees made their first World Series appearance since 2009.

In other injury news, DJ LeMahieu played for the second straight day on a rehab assignment at Triple-A Scranton/Wilkes-Barre on Sunday and could join the team in Seattle this week to make his season debut. LeMahieu had a cortisone injection last week in his right hip, dealing with an injury stemming from last year.