British promoter Frank Warren warns that the loser of Saturday’s heavyweight contest between Joe Joyce and Zhilei Zhang will see their championship aspirations stymied for at least a couple of years.

China’s Zhang (25-1-1, 20 KOs) and London’s Joyce (15-1, 14 KOs) will meet at OVO Arena Wembley tonight in London for their 12-round rematch, five months after Zhang sprang the upset over Joyce in their first encounter with a technical knockout in the sixth round. Joyce lost his WBO interim title as a result. Zhang has been tabbed as the slight favorite in the rematch.

Warren, the head of Queensberry Promotions, which backs Joyce, predicted it will take at least two years for the loser of Saturday’s fight to make his way back to title contention rotation—a potentially devastating outlook as both fighters can hardly be called spring chickens; Joyce is 38, while Zhang is 40.

Warren expects the winner of Zhang-Joyce II to immediately move on to fight for a title against the winner of the undisputed heavyweight championship between Warren’s charge, the WBC titlist Tyson Fury, and Oleksandr Usyk, who holds the remaining three belts (WBO, WBA, and IBF). Warren is hoping that Fury and Usyk will be able to come to an agreement, despite the fact the two sides have been unable to reach a deal on multiple occasions.

Fury (33-0-1, 24 KOs) would also have to come out victorious for his next scheduled fight, a high-profile “crossover” over event against former UFC heavyweight champion Francis Ngannou. That contest is scheduled for Oct. 28 in Saudi Arabia.

Complicating the timeline is the possibility that Usyk’s next fight has to be a defense against the IBF’s top-rated heavyweight contender Filip Hrgovic. Usyk successfully dispatched his WBO mandatory, Daniel Dubois, by late-round stoppage last month in Poland.

“After the unification, you’ve got the IBF and the WBO calling for their respective mandatories, that means the winner of this will be the WBO mandatory challenger and will get a shot next year,” Warren told SecondsOut. “The loser, it could take him a long time to get himself into position for a voluntary, because there won’t be no voluntaries, or getting himself back into the number one spot. That could take two years. So that’s why Joe has asked for it (the rematch). Joe knows what he did wrong last time. And the big question is can he correct it.”

Recently, Fury rejected the idea of fighting Usyk—or any legitimate top boxer for that matter. When asked if that attitude will complicate efforts to stage an undisputed championship bout, Warren offered a coy response.

“We’ll see, those titles are going to have to be defended, there’s no doubt about that,” Warren said. “The winner of this will fight for the WBO version.”

Sean Nam is the author of Murder on Federal Street: Tyrone Everett, the Black Mafia, and the Last Golden Age of Philadelphia Boxing.