UFC 151 has been canceled because light-heavyweight contender Dan Henderson has a knee injury and champion Jon Jones declined UFC President Dana White's request that Jones fight Chael Sonnen in Henderson's place.
"The is the first time ever a sitting champ has turned down a fight and forced a cancellation," UFC Chairman Lorenzo Feritta told The Times.
White says he was surprised and disappointed that Jones turned down a fight with Sonnen, forcing the cancellation.
"We've never, ever had a fighter refuse to fight someone," White said at the news conference announcing the cancellation. "As much as he's won and with all the things he's accomplished in a short amount of time, he's been a champion that hasn't been very popular. I don't think this is going to do wonders for his popularity."
White indicated that he is also unhappy with Jones' trainer, Greg Jackson, calling him a "sport killer" for telling his fighter that accepting the Sonnen fight on short notice would be a mistake.