Shane Carwin looks on during a UFC 131 news conference...

Shane Carwin looks on during a UFC 131 news conference in Vancouver, British Columbia. Carwin is scheduled to fight Junior Dos Santos, of Brazil, in the main event. (June 9, 2011) Credit: AP

Chalk up another main-event altering for the UFC in 2012.

Shane Carwin, who was scheduled to fight against "Ultimate Fighter 16" opposing coach Roy Nelson next month, injured his knee and had to pull out of the bout.

"WOW!! It never ends Carwin blew his knee out," UFC president Dana White tweeted. "Looking for a new opponent for Roy on the TUF Finale on FX."

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