Former welterweight champion Robbie Lawler is out of his Nov. 21 bout against Mike Perry at UFC 255 due to an injury, sources told MMA Fighting's Damon Martin.
The UFC is seeking a replacement to face Perry on short notice, according to ESPN's Ariel Helwani.
Perry wrote on Twitter that he asked the UFC to schedule him to face Khamzat Chimaev in a middleweight bout. But Chimaev is slated to fight Leon Edwards on Dec. 19.
The severity of Lawler's injury isn't clear, nor is a timetable for his return.
Lawler, who's coming off a decision defeat to Neil Magny in August, has lost four straight bouts. The 38-year-old held the belt from 2014 to 2016, recording title defenses against Rory MacDonald and Carlos Condit in "Fight of the Year" candidates.
Perry ended a two-fight skid by beating Mickey Gall via unanimous decision in June.
Perry's ex-wife, Danielle Nickerson, recently said the fighter physically assaulted her multiple times during their relationship. The UFC has yet to formally comment on the accusations.
A flyweight title bout between champion Deiveson Figueiredo and Alex Perez will headline UFC 255. Valentina Shevchenko will defend the women's flyweight belt against Jennifer Maia in the co-main event.