UFC light heavyweight champion Jon Jones is set to make his second title defense against Lyoto Machida, not against Rashad Evans as previously believed, according to ufc.com.

"Alright Toronto!!! Dec 10th UFC 140 tix go on sale next weekend and ur main event is Bones Jones vs Machida!!!" said Dana White, UFC president, through his twitter account.

Both Jones and Machida have verbally agreed to fight one another. Jones recently dispatched Quinton Jackson at UFC 135 via rear naked choke, successfully defending his title for the first time and is currently riding a five fight win streak. Machida last defeated Randy Couture via front kick knockout at UFC 129 and will look to reclaim his title.

As for Evans, the cause for his withdrawal from the grudge match is due to an injury he suffered from his previous fight with Tito Ortiz at UFC 133.

"After my last fight against Tito Ortiz, I dislocated my right thumb, which required it to be set back in place and held with pins. 24 hours ago, my physician removed the pins. At that time, I learned that it would require another three weeks of rehabilitation before engaging in any exercise or training that would require the use of my hand," said Evans in a statement he released on Thursday.

The Jones vs. Evans title fight was one of the more anticipated match-ups, pitting two former teammates with bad blood to boot, but would now have to delayed at least until 2012 assuming that Jones holds on to his title.

"Given the rehabilitation time I require for my dislocated thumb, I would not be 100 percent ready by December 10. The UFC has to keep making fights that entertain the fans. I would have done the same thing as Dana in his position. I'm asking for the fans to support me as I rehabilitate my hand, and I promise I will be back fighting very quickly," added Evans.

UFC 140 is expected to be scheduled on December 10 at the Air Canada Center in Toronto, Ontario, Canada. The Jones vs. Machida light heavyweight title match is to headlined, complemented by the Antonio Rodrigo Nogueira vs. Frank Mir rematch in the co-main event.