UFC middleweight champion Chris Weidman has suffered an injury in training that will require surgery.

Although the surgery is being called “minor,” the 29-year-old’s scheduled title defense against former light heavyweight champion Lyoto Machida on May 24 at UFC 173 in Las Vegas will be pushed back. The pair are now expected to face off at at UFC 175 on July 5, also in Las Vegas. The promotion has yet to reveal a replacement for the headlining spot at UFC 173.

For Weidman, the bout will mark the second defense of his middleweight title. The unbeaten New Yorker captured the belt with a second-round knockout of long-reigning champion Anderson Silva at UFC 162 and then retained it in the pair’s rematch in December at UFC 168. Weidman was originally expected to face former champion Vitor Belfort on the May card, but when the Nevada State Athletic Commission banned therapeutic-use exemptions (TUE) for testosterone-replacement therapy (TRT), Belfort was replaced by Machida.

The Brazilian Machida has picked up two straight wins since dropping to 185 pounds late last year. The karate practitioner scored a violent, first-round head kick knockout of Mark Munoz at UFC Fight Night 30 in October and most recently cruised past former Strikeforce title holder Gegard Mousasi at UFC Fight Night 36 in February.

UFC 175 takes place from the Mandalay Bay Events Center in Las Vegas and airs live on pay-per-view.