Updates: Mayweather, Mares, more

Some news and notes from the boxing world:

• Nevada State Athletic Commission executive director Keith Kizer said Thursday that the post-fight drug tests for Floyd Mayweather Jr., Robert Guerrero, Abner Mares and Daniel Ponce De Leon all came back negative for any prohibited substances. The results for the rest of the boxers on the May 4 card at the MGM Grand and May 3 card at The Cosmopolitan in Las Vegas are still pending. Kizer said all 30 boxers on the two cards were tested.

• Mares looked fantastic knocking out Ponce De Leon in the ninth round to win a featherweight title on the Mayweather-Guerrero undercard, giving Mares a world title in his third weight class in the past three years. Golden Boy Promotions CEO Richard Schaefer said two scenarios are being considered for Mares' first defense. One is for Mares, who lives in Southern California, to return home to his native Mexico for a homecoming fight. The other is for Mares to once again fight on Mayweather’s undercard when he returns Sept. 14 to the MGM Grand.

• A little date switcheroo to fill you in on: Sakio Bika (31-5-2, 21 KOs) and Marco Antonio Periban (20-0, 13 KOs), due to meet for a super middleweight title that was stripped from Andre Ward for no good reason, were scheduled to fight June 8 on the Golden Boy/Showtime card at the Home Depot Center in Carson, Calif. But Schaefer said the fight has been pushed back two weeks and will instead go on a Showtime tripleheader on June 22 on the Paulie Malignaggi-Adrien Broner undercard at the Barclays Center in Brooklyn, N.Y. Also on the card is the heavyweight rematch between Johnathon Banks and Seth Mitchell.

• With Bika-Periban moving to June 22, Schaefer said another fight has been added to the June 8 card to also make it a tripleheader: a junior middleweight fight between hot prospect Jermell Charlo (20-0, 10 KOs), 22, of Houston, and Philadelphia’s Demetrius Hopkins (33-2-1, 13 KOs), 32, the nephew of light heavyweight titlist Bernard Hopkins. The June 8 card is headlined by welterweight Marcos Maidana against Josesito Lopez and also includes a junior middleweight fight between Erislandy Lara and Alfredo Angulo.

• Featherweight prospect Gary Russell Jr. is slated to appear on Showtime on the undercard of light heavyweight titlist Bernard Hopkins’ defense against mandatory challenger Karo Murat at the Barclays Center on July 13. Finding an opponent for Russell is always difficult, and this fight is no different.

“We have made a very strong offer to (former titlist) Jhonny Gonzalez and we’re waiting to hear from him,” Schaefer said.

• When the Canadian super fight between former light heavyweight champ Jean Pascal and former super middleweight titlist Lucian Bute, which was supposed to take place May 25 at the Bell Centre in Montreal, was called off because of Bute’s left hand injury, Pascal promoter Yvon Michel said some of the undercard bouts would be shifted to the June 8 card at the Bell Centre headlined by light heavyweight champ Chad Dawson facing Quebec’s Adonis Stevenson. Michel, who also promotes Stevenson, told ESPN.com that these two bouts would shift to June 8: light heavyweight Eleider Alvarez against Allan Green and welterweight Kevin Bizier versus Aldo Nazareno Rios.

• Up-and-coming lightweight Bahodir “Baha” Mamadjonov (13-1, 9 KOs), 25, a former standout amateur from Uzbekistan now living in Houston, has signed a promotional deal with Don King. Mamadjonov scored an upset on April 12 by knocking out Angelo Santana -- the best prospect in King’s thin stable -- in the ninth round. Mamadjonov had taken the “ShoBox” main event on short notice and impressed in front of a national TV audience.

“Signing with Don King brings me closer to my goal of winning a world championship,” Mamadjonov said. “That is what drives me every day. I want to win a world title for my family and the people of Uzbekistan who always believed in me.”

Said King, “I am extremely pleased and proud to have Baha with me. I expect great things from this young man because he’s dedicated and committed to becoming a world champion. He took the fight with Santana on almost no notice and stopped a great lightweight.”

• Former junior welterweight titlist Gavin Rees (37-2-1, 18 KOs) of Wales, who got knocked out by Adrien Broner in the fifth round in a February world title bout, returns to face England’s Anthony Crolla (25-4-1, 9 KOs) on June 29 in Manchester, England. The fight is the co-feature on the card headlined by former heavyweight titlist David Haye against former title challenger Manuel Charr. Crolla is coming off a 12-round split draw for the Commonwealth lightweight title against Derry Mathews on March 30 in a rematch of a Mathews sixth-round knockout win in April 2012.

“I cannot wait to get back into action,” Rees said. “I am itching to get another world title shot after fighting Broner. He is a megastar and will go on to do massive things in the game, but I feel that I can win another world title and this is a massive fight to prove I still have ambitions at that level.

“Anthony is a very good fighter and he put up a great performance in his rematch with Derry Mathews, and I think that the draw was the fair result. All-British clashes are always great to be a part of, with my own battle against Mathews a real cracking fight."

• Irish featherweight Patrick Hyland (27-1, 12 KOs), who is coming off a decision loss to Javier Fortuna for an interim featherweight title on Dec. 8, was due back in action on May 18 in Poughkeepsie, N.Y. -- near his base of Marlboro, N.Y. -- but the card was canceled on Thursday because Hyland suffered a shoulder injury in his training camp, Final Round Promotions announced.