Eddie Hearn, promoter for IBF, WBA, WBO, IBO heavyweight champion Anthony Joshua (21-0, 20 KOs), says his boxer wants a unification with WBC champion Deontay Wilder (40-0, 39 KOs) - but they don't believe Wilder wants the fight.
Hearn stated in a recent interview that Dillian Whyte is the frontrunner to face Joshua on April 13, at Wembley in London.
But, Joshua will first compete at that venue on September 22nd, against mandatory challenger Alexander Povetkin.
Wilder is heading to a showdown with unbeaten lineal champion Tyson Fury, likely on a November date in Las Vegas.
Joshua and Wilder were in talks for the fall, but the contest fell apart when the two sides were unable to agree on the exact financial terms.
According to Hearn, Wilder and his handlers have been wasting their time.
He wants to make a deal, right now, for Wilder to face Joshua in April.
Wilder still has Fury to contend with - but Hearn has doubts about that contest actually coming off.
"[Joshua] would like to, but he's not interested in time wasters. We've put a contract together based on all the terms that they agreed, and they still haven't even replied," Hearn said to Sky Sports.
"If you don't like those terms anymore after you've accepted them, fine, let's talk about it and try and make it. They don't even want to talk about it. They wait on Fury-Wilder which I don't know, I have my doubts.
"We would like to make the Wilder fight now for April 13, but when you've got a group of people that won't reply to you, or wouldn't meet you to discuss it, how can you possibly make it? We will run out of time."
At the moment, Hearn says Joshua is fully focused on the upcoming fight with Povetkin.
"His frame of mind is really, really focused," Hearn said. "I don't think he's taking a lot of interest in the outside world around this fight, because he knows what's at stake."