Undefeated Featherweight Rafael “Big Bang” Rivera (25-0-2, 16 KOs) will step in to fight 2012 U.S. Olympian Joseph “JoJo” Diaz, Jr. (24-0, 13 KOs) in a 12-round WBC title eliminator as the co-main event to the Canelo-Golovkin clash Saturday night at T-Mobile Arena. Rivera is replacing Jorge Lara, who had to bow out due to reasons that have not been verified.

Rivera was originally supposed to fight Diaz on Saturday’s card, but was forced to step aside for Lara, due to Lara being higher-ranked by the WBC. Rivera has already been training for a fight next week, and is in tip-top shape for his showdown with Diaz.

“Originally, I was hoping to get a shot at JoJo Diaz,” Rivera said. “When that didn’t pan out, I took another fight for next week. I have therefore been training and am in the best shape of my life. I am grateful that I have this last-minute chance, and there is no way I am letting this opportunity pass me by.”

Diaz Jr. said, “I don’t care who is in front of me, I’m leaving with a win on September 16th. After I have my hand raised in victory, I will be one fight away from realizing my dream of winning a world championship.”