Anthony Joshua has been told by the WBO that he has 48 hours to prove that his fight against Tyson Fury can go ahead before he is obliged to face Oleksandr Usyk.
The two Brits have been expected to reach a final agreement on their proposed heavyweights clash billed for Saudi Arabia with August 14 chosen as a preferred date.
But, those plans plunged into throes on Monday after an arbitrary judge ruled that Fury must take on Deontay Wilder in a trilogy bout before September 15.
A clause in their contract allowed for a rematch between Fury and the American, who has refused to back down despite initial hopes that a mouth-watering compensation fee would have him step-aside.
This means Joshua would likely square off against Ukrainian Usyk, and according to Sky Sports the WBO have told Joshua he has just two days to salvage the fight with Fury before taking on a mandatory challenger.
Speaking to the broadcaster, Usyk’s promoter Alexander Krassyuk said: “The WBO is extremely happy as their mandatory challenger will be facing their heavyweight champion.
“What else can they desire? We are waiting for their approval letter!”
And WBO president Paco Valcarcel added: “I hope boxing fans will enjoy Joshua vs Usyk in the near future.
“Usyk said that he was crossing the English Channel by the time he received my message, and asked which turn he should be making. He was happy to hear the news.
“There is no other reasonable excuse for AJ now. If he is not avoiding Usyk, it is high time to face the mandatory! We are now in the position to make the fight happen as soon as possible.”