Eddie Hearn, promoter WBO, WBA, IBF, IBO heavyweight champion Anthony Joshua (21-0, 20 KOs), is concerned with his fighter's upcoming assignment - which is a mandatory world title defense against Alexander Povetkin.
The fight is potentially going to come down on September 22nd, in the UK.
Povetkin, like Joshua, captured a gold medal in the Olympics. He also previously captured the WBA world title.
According to Hearn, he was hoping to match Joshua against WBC heavyweight champion Deontay Wilder - but claims Wilder took too long to sign a contract, and as a result the WBA came down on Joshua and forced him to meet his mandatory obligation.
"We want to beat Povetkin, we want it to be the undisputed fight, but this is a tough fight against Alexander Povetkin, but I believe Joshua beats every heavyweight," said Hearn to Sky Sports.
"I can't wait until the day he gets in the ring with Deontay Wilder. But one side in my opinion is real, and one is not. If you want to prove you're real, sign the contract.
Should Joshua win, he will attempt to fight Wilder in a high stakes unification in April of next year.
And because of that, Hearn is concerned about the contest with Povetikin, who has never been stopped and his only career defeat was a decision loss to a prime version of Wladimir Klitschko back in 2013.
Joshua was forced to get off the floor to stop Klitschko in the eleventh round of their April 2017 war.
"Joshua has got to do what he always does, just handle business, and this Povetkin fight is a tough fight," Hearn said.
"He's only lost once to Klitschko on points and Klitschko hit him with everything, couldn't budge him. He's got an Olympic gold medal, he's got great pedigree, he's got power, he's got speed, he's technically good. This is a dangerous, dangerous fight."