Former middleweight champion Kelly Pavlik (36-2) withdrew from his Nov. 13 fight with Brian Vera because of a rib injury from training, a Top Rank spokesman confirmed to on Monday. Pavlik was scheduled to be the co-main event on the card headlined by Manny Pacquiao and Antonio Margarito at Cowboys Stadium in Arlington, Texas.

Undefeated lightweight Brandon Rios, whose trainer, Robert Garcia, also trains Margarito, is expected to replace Pavlik. Rios, 24, is coming off a disqualification win over Anthony Peterson in September and is considered one of the top young prospects in the division.

For Pavlik, the injury is the latest in a long list of tough breaks that date to his 2008 loss to Bernard Hopkins. Pavlik battled a serious staph infection in 2009 and twice had an anticipated matchup with Paul Williams scuttled because of injury. His only victories since the Hopkins fight have been over Marco Antonio Rubio and Miguel Espino.

Last April, Pavlik lost the middleweight title by unanimous decision to Sergio Martinez. Pavlik had trouble making weight before the fight and was battered and bloodied by Martinez in the later rounds.

Neither Pavlik nor his trainer, Jack Loew, was immediately available for comment.

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