Robert Guerrero celebrates his victory over Joel Casamayor following their junior welterweight boxing match Saturday, July 31, 2010 in Las Vegas. Guerrero won by unanimous decision. Isaac Brekken / AP

Robert Guerrero, left, punches Joel Casamayor during their junior welterweight boxing match Saturday, July 31, 2010 in Las Vegas. Guerrero won by unanimous decision. Isaac Brekken / AP

Rocky Juarez (L) and Jorge Linares pose in the ring after Linares beat Juarez by unanimous decision in their lightweight fight at the Mandalay Bay Events Center July 31, 2010 in Las Vegas, Nevada. Ethan Miller / Getty Images

Rocky Juarez of the US lands on the canvas before being defeated by Jorge Linares of Venezuela during their WBA Fedelatin lightweight bout at the Mandalay Bay Resort in Las Vegas on July 31, 2010. MARK RALSTON / AFP/Getty Images

Jorge Linares (L) of Venezuela lands a punch on Rocky Juarez of the US before defeating him during their WBA Fedelatin lightweight bout at the Mandalay Bay Resort in Las Vegas on July 31, 2010. MARK RALSTON / AFP/Getty Images

Jorge Linares of Venezuela (L) punches Rocky Juarez of the US during their WBA Fedelatin lightweight in Las Vegas, Nevada on July 31, 2010. GABRIEL BOUYS / AFP/Getty Images

Rocky Juarez of the US (L) is counted by the referee as Jorge Linares of Venezuela looks on during their WBA Fedelatin lightweight in Las Vegas, Nevada on July 31, 2010. GABRIEL BOUYS / AFP/Getty Images