Joshua lost his belts in a shock upset to Usyk on September 25, though the Brit has activated a rematch clause in his contract which should see them go at it again at some point later next year.
'AJ' had originally regained his titles in Saudi Arabia when he avenged his defeat to Mexican fighter Andy Ruiz Jr in December 2019.
But Arum - who watched The Gypsy King pick himself up off the canvas en route to a stoppage victory over Deontay Wilder on Saturday night - sees his defeat to the Ukrainian as an ominous sign given Usyk's relative lack of size and reckons Joshua has 'no way' of getting one over on Usyk.
“Eddie [Hearn] thought Joshua wouldn’t be amenable to a step aside and would want to do the rematch," Arum told FightHub.
"Which is sort of stupidity on his part because no way is he going to beat Usyk in his next fight no matter what new strategy he deploys.
“Yeah, too talented, and he’s a little chinny, Joshua is.
"The only way you’re going to beat Usyk is to pin him and corner him with your high weight and pressure him.
“But then he can unload against you. Now, a Tyson Fury can absorb that, as we all know, but Anthony Joshua has a suspect chin."
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Meanwhile, the WBC have recently confirmed that Fury will be ordered to defend his title against Dillian Whyte, as long as he doesn't lose to Otto Wallin on October 30.
While Arum refused to explicitly mention Whyte by name, he did reveal that Fury will return to the ring in either 'March or April', with the intention of facing the winner of Joshua vs Usyk II later in the year.
Arum said: "Joshua and Usyk, I think they’re going to wait until April 4th.
“I think Fury will fight again in March or April. Then we can look to September or October match for a unification."
This article will be updated.News Now - Sport News