Soon after Tyson Fury announced his four-belt heavyweight unification fight with Anthony Joshua for Aug. 14 in Saudi Arabia, an arbitrator ruled that Fury must fight Deontay Wilder in a trilogy bout no later than Sept. 15, according to multiple reports Monday.

The two sides went to arbitration to settle a disagreement over a rematch clause in their contract after Fury and Wilder fought in 2018 and 2020. The arbitrator ruled that Wilder was owed a third fight with Fury.

Wilder was once a perfect 40-0 before fighting to a draw with Fury in December 2018 and then coming away with the first loss of his career in their February 2020 rematch.

Fury promoter Bob Arum told Sports Illustrated the arbitrator's ruling was "preposterous" and Fury's camp plans to move ahead with the Joshua bout on its schedule, hoping to sell Wilder on fighting the winner of Fury-Joshua in November or December.

In a video posted to Twitter on Sunday, Fury said he had assurances from Saudi defense secretary Prince Khalid Abdulaziz Al Saud that the fight with Joshua will take place in Jeddah.

"He told me this fight is 100% on Aug. 14, 2021 ... All eyes on the world will be on the kingdom of Saudi Arabia. And I cannot wait, 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," Fury said.

Joshua, 31, owns the WBA, WBO and IBF belts while Fury is the WBC champion. It's the first time ever that the four heavyweight belts will be contested.

Arum told ESPN that the sides are supposed to get a clean draft on Monday.

The site fee, previously reported by ESPN, is $155 million with the fighters getting $75 million each and an extra $5 million for expenses and undercard.