Bob Arum says there is no chance Tyson Fury and Deontay Wilder will fight in July and the bout could take place early in October due to the coronavirus pandemic.
Wilder took up the option of completing a trilogy with Fury after losing his WBC belt to the Brit in Las Vegas last month.
July 18 had been stated as a potential date for a third battle between the two at the MGM Grand, but Fury's co-promoter ruled out any possibility of that going ahead amid the COVID-19 crisis.
Asked if the fight could be staged in fourth months' time, Arum told ESPN: "Clearly not. We don't even know if the MGM will even be open by then.
"You could not guarantee the fighters that the event would take place on that date. We couldn't convince them or ourselves.
"Where were they going to train for it? It just made no sense. You just have to take a step back. How are you going to sell tickets?
"It's absolutely ridiculous to say the fight is on when the Brits can't even get there.
"So everybody has to take a step back. Boxing is not isolated. It's part of what's happening in the world. So possibly the fight will be in early October."