By Ryan Maquiñana

UPDATE: Sources have advised BoxingScene.com that both Mayfield and Bone have signed contracts but that SpikeTV will choose between them. (Friday 3/13, 11:11am ET)

Karim Mayfield has signed a contract to be a late replacement to fight Shawn Porter in the main event of Friday's "Premier Boxing Champions" card, according to Mayfield's longtime trainer, Ben Bautista.

With Ecuador's Erick Bone (16-1, 8 KOs) the other rumored candidate to replace the ill Roberto Garcia (36-3, 23 KOs) , efforts to contact representatives from Premier Boxing were not immediately returned.

Bautista told BoxingScene.com on Thursday night via text that Mayfield (19-2-1, 11 KOs) will fly in from his hometown of San Francisco and must weigh in at no more than 149 pounds at 8 a.m. Friday morning.

"Porter was preparing to fight Roberto Garcia, whose style is to take to give, and as we know, Karim is completely a different fighter than Roberto," Bautista said. "I want to thank Team Porter, who I am friends with, for the opportunity, as well as everyone that made the fight possible for Team Mayfield."

If the bout is a go, the two camps know each other well, starting with Mayfield and Porter (24-1-1, 15 KO) serving as sparring partners for Manny Pacquiao before the Filipino superstar's fight with Shane Mosley in 2011.

Even more recently, the fighters have crossed paths in the Northern California city of San Carlos, where they both work with nutritionist Victor Conte at his SNAC headquarters.

In fact, both combatants in the co-feature, Andre Berto and Josesito Lopez, have worked with SNAC in varying capacities as well.

Ryan Maquiñana is the Boxing Insider at Comcast SportsNet Bay Area and contributor to KNBR.com. He is a full member of the Boxing Writers Association of America. Email him at rmaquinana@gmail.com or follow him on Twitter @RMaq28.