Joshua and Fury have agreed a deal in principle to fight twice for the undisputed heavyweight world title.
Fury currently holds the WBC belt but will be ordered to face the winner of Saturday’s Fight Camp clash between Dillian Whyte and Alexander Povetkin.
His promoter, Frank Warren, has suggested the Gypsy King has no interest in a bout with Whyte, who has waited over 1000 days for his shot at the world title.
That could see Fury stripped of the WBC belt – and Hearn says that would mean he is no longer Joshua’s priority.
Asked about Frank Warren’s comments that Fury has no interest in fighting Whyte, Hearn replied: “I don’t see why not.
“If he doesn’t fight Wilder, and he’s got a mandatory in Dillian Whyte, and it’s a huge fight which does probably two million pay-per-view buys, why wouldn’t you do the fight?
“The bottom line is that Anthony Joshua wants to win the WBC world title. Whoever is the WBC world champion he will be fighting.
“If Tyson Fury is the guy, he’ll fight Tyson Fury. If Deontay Wilder ’s the guy, he’ll fight Deontay Wilder.
“If Dillian Whyte is the guy and Tyson Fury vacates, he’ll fight Dillian Whyte.
“Right now, Dillian Whyte is in a golden position, actually, but he has to win next week. It’s such a massive fight for his career.”
Asked if there is scope for the agreement in principle between Fury and Joshua to change, Hearn added: “They’ve (Joshua and Fury) just got to keep winning.
“The deal is done and everyone has agreed there’s going to be two fights, but there’s this eight or nine months in the middle.
“There’s going to be ups and downs and uncertainties, maybe a few defeats and maybe it all gets derailed, but the first part of that jigsaw is next Saturday.”
Joshua must first deal with his IBF mandatory challenger, Kubrat Pulev, in a fight Hearn says will happen in 2020 whether in front of fans or not.
“AJ is prepared to fight behind closed doors because he wants to progress his career,” Hearn said. “He needs to fight.
“We want to bring crowds back, obviously, because boxing is better with crowds, there’s no doubt about it, and also it’s a significant part of the pot in terms of revenue.
“We’re desperate for crowds to return but we will continue to innovate and invest to make sure that our fighters can develop and the sport can continue to grow.”
Asked if he will be willing to put Joshua in the ring behind closed doors, Hearn replied: “Yeah, of course. Listen, it’s an adaptation of the numbers and it’s up to me to try and replace that revenue.
“I don’t like the idea of AJ, who has built his whole career on 90,000, 80,000 crowds, fighting behind closed doors.
“But these are unprecedented times, and we won’t let them affect the development of him as a fighter.
“So he will fight this year, either behind closed doors or in front of crowds, but I’m very confident it will be in front of crowds.”