The much-anticipated clash between the two heavyweights will take place on 18 May in Saudi Arabia live on DAZN PPV. This fight, which has already been rescheduled several times, was last postponed due to an eye injury Fury sustained during sparring.
Now, Krassyuk has admitted to Boxing Scene that there are still fears among Usyk's camp that the Brit could yet pull out of another showdown between the pair.
"Usyk has actually had a triple camp for this fight,” Krassyuk said.
“He started in September for the fight to take place last December. We showed up to the Ngannou fight to step in the ring to announce the fight for the undisputed, but his team jumped and said he didn’t look that good, so Usyk gave him some space to prepare at his camp in Saudi Arabia.
"We were then meant to fight on Feb 17, then we were rescheduled for May. Tyson Fury has withdrawn four times already from this fight.
"Remember that we were looking to fight last April; he pulled out of it then, too. That’s why we fought Daniel Dubois. This will be the fourth camp we have had for Tyson Fury.
“I’ve not got too much confidence in the rematch happening, by the way. If Tyson Fury loses, will he have the confidence to step inside the ring again?
"Theoretically, he can, but we all know what happened in the rematch with Wladimir Klitschko.”
Live on DAZN PPV: Canelo vs. Munguia on May 4. Click here for details.