According to Kevin Iole of Yahoo!Sports, Stephan Bonnar has pulled out of his scheduled fight with Matt Hamill at UFC Fight Night 13 due to a torn lateral collateral ligament sustained during jiu-jitsu practice for the upcoming bout.

"I was doing nothing out of the ordinary, just working on my (jiu-jitsu) getting ready for my fight," a downcast Bonnar said. "I heard a pop and I thought, 'Damn, what is this?' I walked around on it a little, but when I got home, it was really stiff and swollen."

Bonnar, whose last bout ended with a submission victory over Eric Schafer at UFC 77, will likely be out for at least six months recovering from the knee injury.

"What really sucks is that if you break your leg, it feels really bad, but you get on crutches and you sit out six weeks and then you're back and you're good to go," Bonnar said. "In this case, there isn't the pain like a broken leg, but I'm out six months instead of six weeks."

No replacement for Bonnar has as of yet been named.