B.J. Penn pulls out of UFC 132

Former UFC lightweight and welterweight champion B.J. Penn will not fight at UFC 132.

A source close to the situation told ESPN.com that Penn's decision stems from an injury that could require rehabilitation. Penn later confirmed in a posting on YouTube on Friday that he won't fight because of a shoulder injury.

The 32-year-old Hawaiian was originally scheduled to fight Jon Fitch in a rematch of a February draw in Sydney, Australia. However last week it was reported that Fitch (23-3-1) would not fight on July 2 because of a shoulder injury suffered while training for the title eliminator rematch.

Penn (16-7-2) returned to competition at 170 pounds last November with an opening-round knockout of Matt Hughes. The move up in weight was prompted by consecutive decision losses to current UFC lightweight campion Frankie Edgar.

Fitch-Penn was set to co-headline UFC 132 in Las Vegas at the MGM Grand Garden Arena. A UFC bantamweight championship fight between Dominick Cruz and Urijah Faber now has top billing.

Josh Gross covers mixed martial arts for ESPN.com.