 On January 11 , 2011 , Lesnar was announced as a coach of The Ultimate Fighter Season 13 , opposite Junior dos Santos , with the two expected to fight on June 11 at UFC 131 , however , he was struck with another bout of diverticulitis and had to withdraw from the fight on May 12 . He was replaced by Shane Carwin , who ended up losing against dos Santos . Lesnar underwent surgery on May 27 to help battle his problems with diverticulitis . Dana White said that he had a 12 @-@ inch piece of his colon removed . 
