Deontay Wilder has started legal action after Tyson Fury abandoned his plans to face the American for a third time.
Fury believes the rematch clause in his contract has expired and will instead fight Agit Kabayel in London on December 5.
But Wilder, who was stopped in the seventh round by Fury in February, believes he has the law on his side.
He and his team intend to begin mediation this week which will involve a retired judge reviewing the contract.
"We’re going into it very optimistically this week," Wilder's manager, Shelly Finkel, told The Athletic .
Fury and Wilder's trilogy clash was due to take place on July 18 before the coronavirus crisis forced it back to October 3.
It was then delayed until December 19 but was again postponed due to a clash with college football in the US.
At that point Fury walked away and will instead fight in the UK for the first time in over two years when he takes on Kabayel at the Royal Albert Hall.
Wilder has recently embarked on a smear campaign, accusing Fury of tampering with his gloves and his own trainer Mark Breland of spiking his water.
The former heavyweight world champion has also blamed his 40lb ring-walk suit, an injury and the referee for his punishing first professional defeat.
Fury said recently: "The original date was July 18. That didn't happen because he had an injury so it got put back three months to October, then that didn't happen because they were trying to get a venue.
"And then they had three dates in December – 5th, 12th, 19th – which I agreed to all them and obviously that didn't happen. So, I'm not going to wait around forever."
