Former cruiserweight champion Usyk, 35, stepped up in weight to strip AJ, 32, of his WBA, IBF, WBO and IBO heavyweight world titles at the Tottenham Hotspur Stadium last September.
The pair will run it back in Saudi Arabia later this month on August 20 with the winner expected to take on Fury in an undisputed bout.
The Gypsy King is currently enjoying a spot of retirement after his April 23 showdown with Dillian Whyte at Wembley Stadium.
But the chance to become the first undisputed heavyweight world champion since Lennox Lewis would be impossible for him to resist according to Arum.
“Well I’ll let you know in a few weeks when the Usyk-Joshua fight takes place,” he told Barbershop Conversations.
“I’m hoping [Oleksandr] Usyk wins because I’ve talked with his people and I think they would be anxious to fight Tyson Fury and I would hope to do that fight in December, maybe, or early next year.
“Robert Garcia is an excellent trainer. He trains a lot of our fighters. We have great respect for him.
“Whether he is able to train a big heavyweight I just don’t know. I don’t know maybe it doesn’t matter, a fighter is a fighter. But again I’m not sure.
“But as far as being a confident trainer he’s one of the best.
“I don’t think he can turn Joshua into what Joshua isn’t.
“I just think Usyk is a much better fighter, much smarter fighter, much quicker fighter and I can’t see how Joshua can beat him. But heavyweights are heavyweights and so we could possibly have a different result.
“I just think Usyk is a better talent and he’s certainly quicker than Joshua. I like Usyk in the fight. But again, could it go the other way? Probably.”
Usyk’s preparation for the rematch with Joshua has been disrupted by Russia’s ongoing invasion of Ukraine.
However, he looks in incredible shape as he closes in on his return to the ring in two weeks’ time.