Tyson Fury has been ordered to face Deontay Wilder for a third time, putting doubt into a proposed summer showdown with Anthony Joshua.
Fury, who defeated the American in their heavyweight rematch last February, is yet to make a defence of his WBC title.
The pair were expected to meet in a third bout until the global pandemic hit and according to promoter Bob Arum, Wilder's rematch clause had expired.
Arbitrator, retired federal judge Daniel Weinstein has reportedly upheld Wilder's claim that he is contractually due another meeting, which must take place before September 15 this year.
It throws a spanner in the worls with a Battle of Britain matchup scheduled for August 14.
While the decision would not necessarily scupper a Fury-Joshua deal, it would require further negotiations and a substantial pay-off in order to persuade Wilder to step aside.
Fury and Wilder fought a split decision draw in December 2018 in Los Angeles, before Fury won their second meeting by seventh-round stoppage in February last year.
Planet Sport reached out to the American's team but they refused to comment.
It comes after Fury revealed he had agreed to take on Joshua - the WBA, IBF and WBO titleholder - on Monday following a conversation with Saudi Arabia's prince.
'I have just got off the phone with Prince Khalid of Saudi Arabia and he told me this fight is 100%, August 14,' Fury claimed.
'All eyes of the world will be on the Kingdom of Saudi Arabia. 'I cannot wait, I repeat, cannot wait to smash Anthony Joshua on the biggest stage of all-time.
'This is going to be the biggest sporting event ever to grace the planet Earth. Do not miss it.'
Wilder has not fought for 15 months and would more than likely prefer a tune-up fight before going back in with the winner of Joshua vs Fury.
A fee of around $8million is believed to be enough to move Wilder aside.
Lennox Lewis received $3million in 1996 to allow Mike Tyson to fight Evander Holyfield.
It is more than likely promoter Eddie Hearn, who has been updating fans, was unaware of the contractual dispute.
The Matchroom boss agreed a site fee of an estimated $150million to stage the content in Saudi Arabia.
Should Joshua and Fury collide, it will be the first time two British fighters have collided for all four major world titles at heavyweight.