By Rick Reeno

Golden Boy Promotions CEO Richard Schaefer has advised BoxingScene.com that Abner Mares (25-0-1, 13KOs) vs. Daniel Ponce De Leon (44-4, 35KOs) will now land in the co-feature position to the big Floyd Mayweather Jr. vs. Robert Guerrero Showtime Pay-Per-View on May 4th at the MGM Grand in Las Vegas.

Mares moves up to 126-pounds to challenge Ponce De Leon for his WBC featherweight title.

The fight was previously scheduled to take place on April 20th at the Home Depot Center in Carson, California - but the fight was moved when Saul "Canelo' Alvarez removed himself from the Mayweather-Guerrero card, and finalized a deal to face Austin Trout in a junior middleweight unification on Showtime's date of April 20th.

"Mares vs. Ponce De Leon will now take place on May 4th as part of the big Mayweather-Guerrero pay-per-view. When it became apparent that Canelo would not be on the card, Floyd Mayweather called me himself and he said that he wants to put together, as he always does on his cards, the best possible fights which are appealing to fight fans. I told him, that one of them is Abner Mares against Ponce De Leon, because it reminds me of Rafael Marquez against Israel Vazquez and you know what happened there. These are two guys who are exciting and always come to fight. And basically his response was three words - 'get it done,' Schaefer told BoxingScene.com.

Schaefer also notes that he's working on another fight for the May 4th pay-per-view, involving the always exciting Leo Santa Cruz (23-0-1, 13KOs), who recently vacated his IBF bantamweight title and plans to debut at 122-pounds.