Eddie Hearn, promoter for Anthony Joshua, believes the winner of his boxer's upcoming fight with Andy Ruiz will potentially have to vacate at least one world title.

Joshua and Ruiz will collide on December 7th in Saudi Arabia, for the IBF, WBA, IBO and WBO heavyweight titles.

In the first bout, Ruiz stopped Joshua in seven rounds after scoring four knockdowns.

But the winner of the rematch will mandatory challenger hanging over his head.

Both Oleksandr Usyk (WBO mandatory) and Kubrat Pulev (IBF mandatory) are waiting in the background.

If either Usyk or Pulev refuse to step aside, it will leave the Ruiz-Joshua winner is a position where a title will have to get vacated.

"Some belt could become vacant," Hearn told Sky Sports. "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."

Usyk, who Hearn co-promotes, is hoping to land the winner of that fight. After cleaning out the cruiserweight division and unifying all four of the major belts in the division, Usyk made his heavyweight debut last month with a stoppage of Chazz Witherspoon.

After that win, he gave Hearn the marching orders to secure a world title fight.

Hearn already stated in a previous interview, that Usyk could end up facing Derek Chisora for the vacant WBO title - should the Joshua-Ruiz winner decide to vacate the belt.

"It's a fight that they could do, potentially even for the WBO world title next year," Hearn stated.