Deontay Wilder may have to wait until October for his chance to avenge his defeat by Tyson Fury.
The American was dethroned as the heavyweight world champion when Fury stopped him in the seventh round last month.
Wilder immediately triggered the rematch clause in his contract with the trilogy fight pencilled in for July 18 at the MGM Grand in Las Vegas.
But with boxing suspended worldwide due to the coronavirus crisis, the fight will now be delayed.
"You could not guarantee the fighters that the event would take place on that date," Fury's promoter Bob Arum told ESPN.
"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."
Fury and Wilde fought to a draw in December 2018 with Fury twice rising from the canvas.
The Brit changed trainers and tactics for the sequel 14 months later and this time it was Wilder who was floored twice before his corner threw in the towel.
The likely change of date also throws a potential undisputed fight between Fury and fellow world champion Anthony Joshua into doubt.
A December date had been discussed with the fight likely to take place in Saudi Arabia assuming Fury beat Wilder again and Joshua saw off the challenge of Kubrat Pulev.
The Bulgarian is due to challenge for Joshua's three belts on June 20 at the Tottenham Hotspur Stadium but that fight could be move to July 25, or later.
