OLEKSANDR USYK is running so short of opponents he could make a switch to MMA or have a never-before fight against Jake Paul.
The Ukrainian great became the first four-belt undisputed heavyweight champion in history by beating Tyson Fury.
But he was forced to vacate his IBF title to proceed their their planned December 21 rematch in Saudi Arabia.
One of Usyk's coaches - Sergey Lapin - predicted another defeat would spell the end of Fury's iconic career.
And it would leave Usyk looking to the likes of MMA or even a spectacle bout with YouTuber-turned-boxer Paul in search of new challenges.
Lapin told : "He's proven he's the best of this generation and, once he's retired Tyson Fury, he will consider his options.
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"Maybe that's dropping down in weight again, or maybe there's a wildcard option on the table for him; be it in the boxing ring, the MMA cage or even Conor McGregor's Bare Knuckle Fighting Championship."
"Can you imagine Usyk and Jon Jones fighting to prove they're the baddest man on the planet?
"Or maybe it's a third fight with Anthony Joshua in the MMA cage?
"Maybe it's Jake Paul at cruiserweight, although Usyk would need to fight him with one hand behind his back though to make it fair."
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Paul, 27, returns over the weekend against ex-UFC star and bare-knuckle boxer Mike Perry, 32.
Meanwhile, Usyk, 37, prepares to rematch Fury, 35, looking to continue his reign of domination at heavyweight.
Lapin added: "Usyk is running out of challenges at heavyweight.
"He accepted the challenge at heavyweight and became the undisputed heavyweight champion of the world, a lot of work went into this achievement.
"After the rematch we will see who will remain in the heavyweight division, but Usyk has now passed this level, everyone who stood in Usyk's way has been overcome.
"We are now set for a rematch with Fury, after that we will know who will be next."