The World Boxing Association has prevented Carl Frampton from taking on Leo Santa Cruz in the summer after ordering the featherweight champion to instead face Abner Mares.
Frampton was eager for a third fight between the pair after losing to Santa Cruz in Las Vegas earlier this year, having previously won the first Stateside bout to claim the WBA title.
After seeing a trilogy blocked, Frampton could now take on fellow Brit and IBF champion Lee Selby at Windsor Park in Northern Ireland later this year.
A WBA statement read: "The World Boxing Association Championship Committee ordered Mexicans featherweight Leo Santa Cruz (33-1-1, 18 KO) super champion and Abner Mares (30-2-1, 15 KO) regular champion working teams to negotiate their upcoming mandatory fight.
"They were given a 30 [day] negotiating period, and should they not reach an agreement, the WBA will summon a purse bid.
"Mares won the regular WBA featherweight title on December 2016, when he defeated unanimously Argentina's Jesus Cuellar, winning the right to face Santa Cruz for the second time."
Santa Cruz took on Mares in 2015, with the former coming out on top in a majority decision.