Anthony Joshua and Tyson Fury could be forced together by a travel ban between the US and UK, according to promoter Bob Arum.
Fury is scheduled to face Deontay Wilder in a third WBC heavyweight championship fight but they are each in their home countries, the UK and the US respectively, an added logistical headache amid the coronavirus pandemic.
"With or without audiences, we can't do [the third fight] while Fury can't get back into the United States due to the travel ban. Wilder couldn't get into England either," Fury's US-based Top Rank promoter Arum exclusively told Sky Sports.
Fury ended Wilder's title reign earlier this year in their second fight, after a dramatic draw when they originally met.
Asked if travel logistics could lead to Fury instead facing his fellow Brit, the IBF, WBA and WBO champion Joshua, then revisiting his Wilder rivalry next year, Arum said: "Everything is possible.
"We are all operating in territory where nobody has experience. I'm 88 but I've never had the experience to deal with this. We're feeling our way.
"But everything is possible and nothing is off the table. We have to sit and discuss this, to figure out how to move into the future.
"I can't predict when Fury vs Wilder will take place or if it will happen.
"Everybody in the UK wants to see the two Brits fighting, Fury and Joshua. When can that happen? I don't know. I also promote Kubrat Pulev and we're talking next week to Eddie Hearn about how to do [Joshua vs Pulev]."
Joshua is scheduled to defend his belts against mandatory challenger Pulev next.
"This is not a normal situation where the promoter has all the answers," Arum said.
Staging boxing events without spectators is a leading option for promoters on both sides of the Atlantic.
But Arum warned: "If we do fights without audiences, how do you do Fury vs Wilder without an audience? The live gate for the last fight accounted for almost $17m. How do you replace that?
"Hopefully by the winter they will allow people to attend sporting events."
Wilder had previously rejected speculation that he could come to an agreement to step away from his right to face Fury again, and enable Joshua to step in.
Wilder said: "Why wouldn't I want it?
"He knows that wasn't me. I know that wasn't me. That wasn't the real Deontay Wilder, something was wrong.
"There is more fuel on the fire. This is the final straw."