Former UFC Heavyweight Champion Brock Lesnar has once again been stricken with diverticulitis and has been forced to withdraw from his UFC 131 bout against fellow TUF 13 coach Junior “Cigano” dos Santos. The news was officially announced by UFC President Dana White this afternoon.

As a result of Lesnar’s illness, the June 11th card has undergone a change. Former title challenger Shane Carwin will now step in to face dos Santos in the night’s main event, while Carwin’s original opponent on the card, UFC newcomer Jon Olav Einemo, will face an opponent to be determined.

The bout between dos Santos and Carwin, both 12-1-0, will determine the next challenger to Cain Velasquez’s UFC Heavyweight Championship, according to Dana White. Dos Santos has won all six of his fights inside the Octagon, with only his most recent outing against Roy “Big Country” Nelson making it to a decision. Carwin has never gone the distance in his career and is unbeaten save for a loss to Lesnar in the pair’s UFC 116 title fight last July. However, he has not fought since then.

With both fighters preferring to end their fights by knockout, fans may be in for an exciting main event when the UFC returns to Vancouver, British Columbia, Canada for UFC 131.

Lesnar reportedly spent all of yesterday at the renowned Mayo Clinic and must now choose between fighting the illness once again or undergoing surgery. The former champion promises that his career is not over and that he will fight inside the Octagon again.

UFC 131 takes place on June 11th at the Rogers Arena in Vancouver, British Columbia, Canada.

UFC 131 Fight Card (subject to change):

– Junior “Cigano” dos Santos vs Shane Carwin
– Jon Olav Einemo vs TBD
– Donald “Cowboy” Cerrone vs Mac Danzig
– Demian Maia vs “The Filipino Wrecking Machine” Mark Munoz
– Diego “The Gun” Nunes vs Kenny “KenFlo” Florian

– Yves “Thugjitsu Master” Edwards vs Sam “Hands of Stone” Stout
– Jesse “Water” Bongfeldt vs Chris “All-American” Weidman

– Dustin “The Diamond” Poirier vs Jason “Shotgun” Young
– Krzysztof “The Polish Experiment” Soszynski vs Igor “The Duke” Pokrajac
– Nick “The Promise” Ring vs James Head
– Dave “Pee-Wee” Herman vs Joey “The Mexicutioner” Beltran
– Michihiro Omigawa vs Darren Elkins

(Photo Credit: Sherdog.com)