London - World heavyweight champion Anthony Joshua's next fight is "very likely" to be against Deontay Wilder or Alexander Povetkin, promoter Eddie Hearn said on Friday.
Joshua unified the World Boxing Association (WBA), International Boxing Federation and World Boxing Organisation heavyweight titles by outpointing New Zealand's Joseph Parker in Cardiff last weekend.
The Briton then immediately called out Wilder, who holds the World Boxing Council version of the heavyweight title, but a fight with the American - who like Joshua has an unbeaten professional record - may have to wait after the WBA ordered Joshua to enter into talks with mandatory challenger Povetkin.
"The WBA called the mandatory yesterday for AJ to face Povetkin next," Hearn told Sky Sports.
"We have a 30-day window to negotiate - at this stage it means it's very likely Anthony's next fight will be between Wilder or Povetkin."
Seemingly the only way Joshua could hold onto his WBA title and face Wilder next up was if the Russian agreed to a fight at a later date.
Povetkin, whose only defeat in a 35-fight professional career came against Wladimir Klitschko in October 2013, demonstrated his punching power with a brutal knockout of Britain's David Price on the Joshua-Parker undercard at Cardiff's Principality Stadium.
World Boxing, Povetkin's promoters, said on Twitter: "Povetkin is now a mandatory contender of @anthonyfjoshua
"He was appointed by WBA. Now there are 150 days to arrange the fight, it must take place.
"Before the fight with Sasha (Povetkin), Joshua has no right to fight with anybody else. We have 30 days to negotiate@EddieHearn".