Timothy Bradley, right, head butts Nate Campbell in the third round of a WBO Junior Welterweight Championship boxing match in Rancho Mirage, Calif...

Timothy Bradley, right, head butts Nate Campbell in the third round of a WBO Junior Welterweight Championship boxing match in Rancho Mirage, Calif...

Timothy Bradley celebrates a TKO over Nate Campbell (not shown) after a WBO Junior Welterweight Championship boxing match in Rancho Mirage, Calif., Saturday, Aug...

Tim Bradley and Nate Campbell

Former welterweight unified world champion Nate Campbell is interviewed at a news conference to announce his upcoming boxing match against unbeaten junior welterweight...

...belt, at a news conference to announce an upcoming boxing match against former unified world champion Nate Campbell, not shown, in Pasadena, Calif., Wednesday, June 24, 2009. The bout is scheduled Aug. 1 at...

Unbeaten junior welterweight world champion Timothy Bradley, left, strikes a pose with former unified world champion Nate Campbell, at a news conference to announce their upcoming boxing match, in Pasadena, Calif., Wednesday, June 24...

Nate Campbell (L) of the US celebrates victory over Mexican Juan Diaz after their professional boxing WBC World...

Losing his titles on the scale hurt Nate Campbell, right, more than any of Ali Funeka's punches

Feb. 13, 2009: Sunrise, FL - Nate Campbell and Ali Funeka, weigh-in and face off for their upcoming IBF/WBO/WBA Lightweight Championship...

Nate Campbell, Ali Funeka

MELBOURNE, AUSTRALIA - FEBRUARY 23: Nate Campbell of the USA looks dejected during his IBF Super Featherweight World Title bout against Robbie Peden...

Juan Diaz, left, of Houston, Texas, exchanges punches with Nate Campbell of Florida, during their Lightweight World Championship Unification fight in Cancun Mexico, Saturday, March.8, 2008...

Juan Diaz, left, of Houston, exchanges punches with Nate Campbell, of Florida, during their Lightweight World Championship Unification fight in Cancun, Mexico, Saturday, March 8, 2008...

MELBOURNE, AUSTRALIA - FEBRUARY 23: Nate Campbell of the USA looks dejected during his IBF Super Featherweight World Title bout against Robbie Peden...