Anthony Joshua vs. Deontay Wilder is "100 percent happening" but has suffered delay partly due to the announcement of Gennady Golovkin vs. Canelo Alvarez, according to promoter Eddie Hearn.
The rematch between Golovkin and Alvarez was announced for September 15, and due to timing of that fight and various time constraints, Joshua vs. Wilder will have to be delayed.
"We made an improved offer [to Wilder's team] about four weeks ago," Hearn told iFL TV. "On Monday they emailed us saying they accept the terms, now we want to see a contract.
"We wanted to do the event in September. Our original offer was based on a September fight.
"Obviously Canelo-Golovkin was announced and it's only 10 or 11 weeks to September 15.
"Because of how long they've [Wilder's team] taken to come back, September's out. It doesn't work for US TV. It doesn't work in a build-up sense either.
"We're looking now -- if we do Wilder -- for more like October, November.
"Josh wants to do this fight at Wembley, we all do. But we can't do the fight in Wembley if it's not in September. Now we're looking at Cardiff. Now we've got to go back to them, go through the dates etc.
"There's rematch provisions in there. If Wilder becomes the A side, we have no problem going to America. But Josh just felt this fight should go to the UK.
"I'm glad the fight will happen in the UK when it does."
Despite the long process, Hearn remains adamant that the fight does eventually get made.
"The Wilder fight is 100 percent happening," he added. "The max you're going to have to wait is seven or eight months. But hopefully you might have to wait three or four months. I'm almost certain this gets signed.
"We are under pressure time wise so I'm hoping they come back in good time on the contract because if they are going to mess around, and it's not going to get done, we'll jump in and fight Povetkin in September.
"We can sign for Wilder now for December or for February, no problem. But I'm not going to wait until July or August and still not have a fight scheduled."
Joshua's last outing was a point's victory over Joseph Parker, while Wilder beat Luis Ortiz also earlier this year.