Benson Henderson is out of his 160-pound catchweight bout against Michael Chandler at Bellator Japan on Dec. 29, promotion officials announced Thursday morning.
"Smooth" has been replaced by top prospect Sidney Outlaw.
Henderson, a former UFC lightweight champion, apologized for having to withdraw from the contest due to an injury in a video posted by Rizin FF, which is co-promoting the event.
"I just wanted to take the time to apologize and say that I got an injury and I will not be able to participate in the Dec. 29 festivities in Japan, so I won't make it out there," Henderson said. "I'm hoping that Bellator sets it up, reschedules it for later on, Chandler and I, and we can be able to settle some things."
Henderson didn't reveal any specific details regarding his injury, nor his timetable for return.
Chandler defeated Henderson by split decision at Bellator 165 in November 2016. It was the first title defense of Chandler's second stint as the Bellator lightweight champion.
Since then, Chandler has gone 3-2, including dropping the lightweight title to Brent Primus, recapturing it in a rematch, and then losing it again to Patricio Freire in May.
Outlaw, 27, made his Bellator debut last month, defeating veteran Roger Huerta by decision at Bellator 234. Outlaw has fought for numerous regional promotions, including Titan FC, Ring of Combat, CFFC, and Dana White's Contender Series. He's riding a nine-fight winning streak.
Bellator Japan, which takes place in Saitama, will be headlined by a heavyweight bout between Fedor Emelianenko and Quinton "Rampage" Jackson.