Rival British promoters Frank Warren and Eddie Hearn have not given up hope of matching Tyson Fury and Anthony Joshua for all four world heavyweight titles in 2020.
A clash between the two English boxers is now potentially the biggest fight to be made in world boxing after Fury's stunning seventh-round win over Deontay Wilder for the WBC title in Las Vegas on Saturday.
But there are obstacles in place that could prevent Fury versus Joshua from happening next, or this year, due to rematch clauses and mandatory defences against other opponents.
As part of the deal to make last Saturday's Wilder-Fury rematch, the loser -- Wilder -- has 25 days from last Saturday to invoke the rematch clause to make a third fight. Wilder told ESPN on Monday: "We're definitely going to exercise it," but Fury's co-promoter Warren believes the 'Gypsy King' could still face WBA-IBF-WBO champion Joshua in late 2020.
A third fight between Fury (30-0-1, 21 KOs) and Wilder (42-1-1, 41 KOs), after their first meeting ended in a points draw in December 2018, would take place at a venue in the United States, likely back in Vegas, between July and October.
"There's demand from everywhere for Fury versus Joshua, but if he [Wilder] does ask for the fight we have to get on with it. Everyone went into that contract with their eyes open, so it's not a shock," Warren told ESPN.
"It will be Tyson's decision what he does next and I'm not rushing him -- he deserves a rest, there's plenty of time to sort it out.
"We've not heard from Wilder yet, the clock is ticking, but I'm sure he will do it again. Why wouldn't they?
"The third Wilder fight will have to happen by June or July and we have a great chance of then seeing [Fury versus Joshua] happen. But Joshua has got his mandatories, two of them, which he has to win, and we've seen what happens when he gets hit on the chin.
"I would prefer to go straight to Joshua, but if Wilder wants the rematch, it has to be honoured."
Warren and Hearn have not had any contact yet, but Hearn has had talks with Top Rank promoter Bob Arum, who co-promotes Fury, and Fury's management company MTK Global.
Joshua (23-1, 21 KOs) is set to defend his belts against Bulgaria's Kubrat Pulev, the mandatory challenger for his IBF belt, reportedly at the Tottenham Hotspur Stadium in London on June 20. Ukraine's Oleksandr Usyk, the former world cruiserweight champion now operating at heavyweight, is another mandatory defence awaiting Joshua.
"I've spoken in depth to MTK and Bob Arum, and everyone shares the same vision," Hearn told ESPN.
"If we don't fight Fury next, then it will be very difficult to make it an undisputed fight. While Arum may be able to do a deal with Pulev, Usyk is next if he beats Dereck Chisora.
"I don't think [Fury versus Joshua] is a year away, but obviously if Wilder does choose to rematch then it won't be next for us. Anything can happen though at this stage."
Warren has not ruled out making Wilder an offer to step aside, allowing Fury to face Joshua next, assuming Joshua's promoter Hearn makes a similar arrangement with Pulev.
"We will have to see what happens. At the end of the day it's down to Tyson and I don't care about anything else, it's what he wants to do," Warren told ESPN.
Warren is not concerned about a mandatory obligation to defend the WBC title against Dillian Whyte, of England, getting in the way of a possible fight between Fury and Joshua after their fights with Wilder and Pulev this summer.
"The Whyte fight is not until next February, the time is there to fit it all in," Warren told ESPN.
Hearn, who promotes Whyte, told ESPN: "The WBC mandatory is due in February 2021 and while we don't agree with this date, Dillian is in a great spot in all this. Right now, he is the official mandatory challenger to Tyson Fury."