Unbeaten 130-pounders to meet

Any time there's a big fight in Las Vegas, a smaller card usually lands on the schedule there the night before. It will be no different when pound-for-pound king Floyd Mayweather Jr. defends his welterweight title against Robert Guerrero on May 4 at the MGM Grand.

On May 3, Golden Boy, which is promoting Mayweather-Guerrero, will also put on a card at The Cosmopolitan (Fox Deportes/FNS, 11 p.m. ET).

In the main event, junior lightweight prospect Francisco Vargas (15-0-1, 12 KOs), a 2008 Mexican Olympian, will take on Jose Aguiniga (33-0, 15 KOs), who quit fighting from 2007 until last year, in a scheduled 10-rounder.

The co-feature isn't set yet, but 2012 U.S. Olympians Errol Spence Jr. (4-0, 3 KOs), a welterweight, and Joseph Diaz (3-0, 1 KO), a junior featherweight, will face opponents to be determined in scheduled six-round undercard bouts.

Santana back in action

Promoter Don King announced a Las Vegas fight card for April 12 at Treasure Island Resort & Casino. Lightweight prospect Angelo "La Cobra" Santana (14-0, 11 KOs), a former Cuban amateur standout living in Miami, will headline the Showtime "ShoBox: The New Generation" card (10 p.m. ET/PT) against Carlos Cardenas (20-6-1, 13 KOs) of Venezuela. They'll meet for a vacant interim lightweight title.

In the eight-round co-feature, Albany, N.Y., junior welterweight Amir Imam (8-0, 7 KOs) will meet Jeremy Bryan (16-2, 7 KOs) of Paterson, N.J.

In a fight not slated for the U.S. telecast, King said that Ryan Coyne (21-0, 9 KOs) of St. Louis will face Marcus Oliveira (24-0-1, 19 KOs) of Lawrence, Kan., in a light heavyweight title eliminator. The winner of the 12-rounder will become the mandatory challenger for titlist Beibut Shumenov.