Middleweight world titleholder Gennadiy Golovkin has suffered a right calf injury that is likely to once again push back his mandatory defense against Kamil Szeremeta, sources told ESPN.

Golovkin and his team have filed for an extension with the IBF, and the fight now will likely take place in May or June, sources said.

Previously, Matchroom Boxing promoter Eddie Hearn told ESPN last week that the fight, which initially had been planned for Feb. 29 before being moved back for various reasons to March 28, likely wouldn't happen until at least April.

A DAZN spokesperson confirmed the promotion is looking at new dates for Golovkin-Szeremeta. Tom Loeffler of GGG Promotions declined to comment when reached by ESPN.

Golovkin (40-1-1, 35 KOs), who turns 38 in April, most recently won a vacant 160-pound world title by edging Sergiy Derevyanchenko by decision on Oct. 5 at Madison Square Garden in New York.

Regardless of when the Szeremeta fight takes place, Golovkin will prepare for it with a different camp. One month after joining Victor Conte's physical conditioning program at his SNAC facilities in San Carlos, California, the two sides have decided to part ways.

"We did our best to help Gennadiy, but he was simply not able to do what we asked him to do," Conte told ESPN on Tuesday afternoon. "In short, I asked him to leave our facility because he did not comply with what we had agreed upon before camp started. However, I do wish him good luck in the future."