UFC heavyweight champion Cain Velasquez (13-1) will be sidelined likely until late 2014 after he underwent surgery on his left shoulder Tuesday.

Velasquez suffered a torn labrum in his Sept. 19 title defense over Junior Dos Santos in Houston.

At first, the belief was Velasquez would not need surgery, which is why the operation took place nearly three months after the injury.

"When the fight was over, Cain basically told me, 'I think I hurt my shoulder again', this was after the fight was over," said Velasquez' trainer Javier Mendez. "If he knew he was injured during the fight, he didn't tell us.

"After he cooled down, he was still hurting, so we went to get an MRI. The first one we got was inconclusive if there was any damage. The second one showed a slight tear and the suggestion was to rehab it for a few weeks and then see how it was healing. The following MRI didn't show any improvement, so he decided to get surgery. He didn't want to, but he really had no other choice. He went under the knife Tuesday and the surgery went well. Now it's a matter of rehab and if he avoids any injuries, how soon he can get back in shape."

Bob Cook, who manages Velasquez, stated that they believe the injury took place when Dos Santos whizzered Velasquez in an attempt to defend a takedown. Velasquez dominated the fight, winning every round en route to a fifth round stoppage.

"My shoulder surgery yesterday went well. Can't wait to be back at it!," Velasquez posted on Wednesday.

UFC president Dana White, via text message, said that he was told Velasquez would be unable to train on he shoulder for six months, which, even if all goes well, would with a full camp, probably mean fall 2014 at the earliest.

Ariel Helwani on 'UFC Tonight' on Wednesday reported that White was interested in having Fabricio Werdum, the top contender, fight before Velasquez would be ready to return against the winner of Josh Barnett vs. Travis Browne.

The injury was to a different shoulder than Velasquez had surgery on in early 2011. Velasquez tore the rotator cuff in his right shoulder during his first heavyweight title win over Brock Lesnar. He also tried to avoid surgery from that injury, but two months later went under the knife and it was a full year before he could return, in a match where he suffered his lone career loss, to Dos Santos.

Velasquez has been one of the most dominant fighters, regardless of weight, in UFC history, with an 11-1 record in the organization. Aside from his knockout loss to Dos Santos, he has nine wins via stoppage and has won 23 of 24 rounds he's fought.

"It happened at the worst time for him because he's got so many fighters he can get out of the way," said Mendez. "And he's still learning. He's the baddest man on the planet, but you can always be a better kickboxer, you can always be a better boxer, you can always improve your wrestling. The goal is to keep getting better and keep defending the title. His goal wasn't to just be a champion, but it was to defend it for a long time."