UFC president Dana White said it is difficult to imagine a scenario in which the rumoured cross-sport fight between world champion boxer Floyd Mayweather Jr and mixed-martial arts star Conor McGregor would ever happen.
Just look at all the years it took Mayweather to agree to and organize his 2015 bout with Manny Pacquiao, White said.
"Let me put it to you this way," White told ESPN's 'Russillo and Kanell' on Thursday. "Manny Pacquiao and Floyd Mayweather are in the same sport. It took how long for those two to fight? Now imagine how hard it would be to get [Mayweather and McGregor] to fight. They're not in the same sport."
Mayweather, who would need to come out of retirement to fight again, and McGregor have stirred the pot about what would be an unprecedented event between the two.
The novelty of such a bout, combined with the notoriety of both fighters, would be expected to draw an impressive purse, one that could rival the Mayweather-Pacquiao bout that brought in $400million in pay-per-view revenue and $72m in ticket sales.
The fight between the superpowers had been talked about in boxing circles for the better part of a decade before the sides finally agreed to meet.
Mayweather won by unanimous decision. He last fought in September against Andre Berto, billed as the final of his career. But Mayweather sits at 49-0 and most believe the temptation to chase career win number 50 and the money that comes with it will prove too great for him to resist.
McGregor, UFC's featherweight champion, also has made headlines by pulling out of UFC 200 because he refused to halt training to promote the event.
Any talk thus far of a fight between Mayweather and McGregor is farfetched, White said. But Mayweather teased the masses last week, saying it is "possible."
McGregor, ever the showman, shared a photoshopped picture on his Twitter account showing the two squaring off.
White does not see how it could work.
"Is this thing going to be MMA or boxing rules?" he said.
"Who's getting the lion's share of the money? This and that. It's impossible. But like I've said, 'Floyd, you want to fight Conor, call me.'"