Promoter Eddie Hearn, who guides the career of IBF, WBO, WBA, IBO heavyweight champion Anthony Joshua (21-0, 20 KOs), believes WBC champion Deontay Wilder (40-0, 39 KOs) is looking to go in another direction.
Fans are in suspense, as Hearn sent over a contract for the bout - after both parties finally agreed to stage the fight in the UK.
But Wilder has yet to sign the contract, which Hearn claims the boxer has held for at least a week.
Initially, Wilder's handlers offered a guarantee of $50 million - but Joshua had no interest in fighting in the United States.
Hearn made a counter-offer, which Wilder and his team eventually accepted. They requested a contract, which Hearn sent.
"They made us an offer, we asked to see a contract, they refused to send one. We made them another offer, after nearly four weeks they accepted and asked for a contract and we sent them one. If they want the fight they will sign it," Hearn told Sky Sports.
Hearn believes Wilder is mentally unstable when it comes to the reality of the negotiations.
A decision will have to come down, sooner than later, because Joshua was ordered by the World Boxing Association to make a mandatory defense against Alexander Povetkin of Russia.
Wilder vs. Joshua was targeted for September. Because so much time has passed in their discussions, Hearn says the showdown would now have to happen in October or November, or even the first quarter of 2019.
"I can't quite make out whether people are lying to Deontay about the negotiations or he is just completely deluded. I saw an interview with him yesterday saying he is actually two people, Deontay Wilder and The Bronze Bomber so I'm siding with deluded. It's not complicated - we have set out the terms of the deal, we put it in a contract and sent it to him," Hearn said.
"He has now had the contract a week. We are getting calls from the WBA on a daily basis asking what's happening, there is absolutely zero urgency from Deontay and his team other than posting silly Instagram videos. The proof is in the resumes and at this stage I believe Deontay and his team do not want this fight."