Ultimate Fighting Championship (UFC) lightweight champion Anthony "Showtime" Pettis has suffered a knee injury in August when he fought Benson Henderson in UFC 164. He is expected to compete on his first title fight against Josh Thomson on Dec 14, but his injury has forced him to withdraw from the said event.

MMAWeekly.com has initially reported that Pettis will still fight Thomson on UFC 9. "Pettis is going to fight, that's for sure," said UFC President Dana White. It was reported that Thomson has been seeing a specialist for the last few days to help him recuperate fast.

Unfortunately, Pettis has to wait a little longer than he had hoped for to defend his title. The fight between Pettis and Thomson has been moved to a later date. The new main event for UFC will be a bout for the flyweight title between Joseph Benavidez and Demetrius Johnson, which was originally set for The Ultimate Fighter 18 Finale.

With that being said and because of the changes, The Ultimate Fighter 18 Finale will have a new main event. It will be a lightweight bout between Gray Maynard and Nate Diaz.

Pettis has not commented on the news, and it is not clear when he will be able to fight again. It is the second time in 2013 that he has postponed a fight. In early August, he was set to have a fight with UFC featherweight champion Jose Aldo but pulled out after hurting his knee while training in Brazil.

As for Thomson, it probably sucks for him. He already had a chance for a title shot. Now that Pettis is unable to fight, he has to wait for Pettis to recover or maybe even fight someone else. If Thomson loses, he may have to wait forever again for another shot at a title.