Former UFC heavyweight champion Brock Lesnar on Thursday pulled out of his bout with Junior dos Santos because of diverticulitis, a digestive disorder.
Lesnar (5-2-0) was scheduled to face dos Santos on June 11 at UFC 131 in Vancouver, British Columbia.
Dos Santos will now face Shane Carwin in the heavyweight title eliminator.
Lesnar was forced to pull out of a fight with Carwin in October 2009, shortly after learning that he had both mononucleosis and diverticulitis. He underwent surgery and defeated Carwin by submission (arm triangle choke) in the second round at UFC 116 in July 2010.
Despite this current bout with diverticulitis, Lesnar has no intention at this time of calling it a career.
"I'll tell you one thing, I'm not retiring," Lesnar told ESPN.com on a UFC conference call. "This isn't the end of my fight career.
"I have a strong faith that there is a solution to every problem. We just have to find the right solution to fix this problem," he said.
Lesnar and dos Santos were opposing coaches on "The Ultimate Fighter Season 13." The winner of the fight was slated to face current UFC heavyweight titleholder Cain Velasquez.
Dos Santos will take a record of 12-1-0 into his fight against Carwin, who is also 12-1-0.
Franklin McNeil covers mixed martial arts and boxing for ESPN.com. Follow him on Twitter at www.twitter.com/Franklin_McNeil.