Disappointing news coming from Dana White this afternoon:  He announced that Dan Henderson has been injured during training and will be unable to compete at UFC 151 against Jon Jones.  Henderson, who has a partially torn MCL, was set to face Jones for the Light Heavyweight Championship on Sept. 1 in Las Vegas, Nev.

This loss has forced Dana White to cancel the event completely.

"This is probably one of my all time lows as UFC president over the last 11 years," White said. "For the first time in 11 years, we're going to cancel an event. Dan Henderson has a partial tear in his MCL. He tried to train, he tried to continue. There was nothing we could do to save that fight."

Henderson's replacement is Vitor Belfort, who will face Jones in Toronto at UFC 152 on Sept. 22 instead.

White said that Chael Sonnen offered to fight Jones with only eight days notice, but Jones declined the match.

"The one thing that I never thought in a million years would happen, happened. Jon Jones said I'm not fighting Chael Sonnen on eight days notice," said White.

We'll keep you updated with further developments as they happen.