Pulev is the mandatory challenger for the IBF heavyweight title, while Usyk is the mandatory challenger for the WBO.
With both titles on the line in Ruiz and Joshua’s rematch in Saudi Arabia, it is unclear who the winner will be mandated to fight, but the Bulgarian’s promoters are confident it will be Pulev.
“Kubrat Pulev’s next fight will be for the IBF world heavyweight title,” his promoters Top Rank told Sky Sports.
“If the Joshua-Ruiz winner decides not to fight Pulev, his next fight will be for the vacant IBF title.”
Pulev has been beaten only once in 29 previous fights, and earned his position as mandatory challenger for the IBF title with victory over Hughie Fury.
It seems likely that one of the two titles will be vacated by the victor of Ruiz-Joshua, unless an agreement can be reached between the two organisations.
Eddie Hearn, Josua’s promoter, has previously discussed the difficult issue.
“We’re going to have a problem where [Usyk and Pulev] both say: ‘you’ve got to fight me next’,” Hearn said to Sky Sports.
“Some belt could become vacant, because the IBF and the WBO are both going to order their mandatories after Joshua-Ruiz Jr.
“Unless a deal can be done with someone, you’ve either got to do that, or vacate.”
Joshua and Ruiz meet on December 7 in Diriyah, Saudi Arabia.