Deontay Wilder says he was told by an insider that Tyson Fury was getting beaten up in sparring in the build-up to their trilogy fight.
Fury will defend his WBC heavyweight championship against Wilder on October 9 in Las Vegas, after Anthony Joshua puts his IBF, WBA and WBO belts on the line against Oleksandr Usyk at the Tottenham Hotspur Stadium on September 25, live on Sky Sports Box Office.
Fury postponed his fight after contracting Covid-19 but Wilder has now told the PBC podcast: "I'm ready. I hope they are ready. I hope they have their priorities in line. Their game-plan, how they are going to approach the fight.
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"I know he wasn't doing well in camp. The young guys were piecing him up.
"I had a young guy from my camp who was piecing him up."
Wilder's new trainer Malik Scott previously told the same podcast: "When you hear those kinds of rumours with this type of high calibre fight, those are not rumours, those are facts."
Fury used Michael Hunter, Christian Thun, Jared Anderson and Efe Ajagba among his sparring partners for his third fight with Wilder.
Wilder said about his own preparations: "Sparring has been amazing. I can't say names but just know there have been a lot of people on the canvas."
He said about Fury: "Hopefully he is confident to go through [with the fight] and not have anything go wrong."
He promised his fans: "A reinvented Deontay Wilder. Something you've never seen before.
"In the time off we have done nothing but work, work, work.
"Even when my body rested, my mind was still at it."
After losing his championship belt and his undefeated record when they last met, Wilder attributed his first defeat to a ring-walk outfit which tired his legs, a "disloyal" trainer throwing in the towel (who has now been discarded) and Fury illegally tampering with his gloves (which the WBC have ruled out).
Wilder has now said: "People don't understand. They don't know what happened. They don't know the truth.
"How I handled myself? I know the ultimate truth whether people believe it or not.
"The key to victory is having a violent mind but approaching it with calmness.
"My silence is golden. Silence is key to it all, that's why I didn't speak at the press conference. There is nothing to say.
"So many people have gone against me. They have seen proof but they don't care.
"My mind-set is violent."
Wilder said about ditching Mark Breland, the trainer who threw in the towel to end his previous fight with Fury: "I had to get rid of the snakes in my team and I had to get in people who really love me. I needed soldiers.
"I'm a king. When a king falls he has to strategise, and get back up. There is no point in moping, sitting back. You've got to pick yourself up, make yourself and the people around you stronger."
Sky Sports Boxing schedule
Oscar Valdez vs Robson Conceicao - WBC super-featherweight title
September 25 - Sky Sports Box Office
Anthony Joshua vs Oleksandr Usyk - IBF, WBA, WBO heavyweight titles
Lawrence Okolie vs Dilan Prasovic - WBO cruiserweight title
Chris Eubank Jr vs Sven Elbir
David Avanesyan vs Liam Taylor - European welterweight title
Richard Riakpohre vs Krzysztof Twardowski
Mikael Lawal vs Steven Ward
Savannah Marshall vs Lolita Muzeya - WBO middleweight title
Hughie Fury vs Christian Hammer
Jamel Herring vs Shakur Stevenson - WBO super-featherweight title
Josh Taylor vs Jack Catterall - undisputed super-lightweight title