Oleksandr Usyk has been accused of being 'spooked' by Fabio Wardley, prompting his pursuit of a fight against Deontay Wilder.
IBF, WBA and WBC heavyweight champion Usyk raised eyebrows by calling out former title-holder Wilder, who stock has plummeted after two high-profile recent defeats.
Usyk vacated his WBO belt which is now around the waist of Wardley, whose manager insists Usyk is avoiding a fight with the Brit.
"Usyk clearly isn't interested in preserving the competitive nature of boxing or honouring his mandatories," Wardley's manager Michael Ofo told ESPN.
"Let's be honest -- Fabio is one of the most in-form heavyweights in the world right now. He's undefeated, he's coming off statement wins, he's young, hungry and active.
"So yeah -- it's disappointing he's not mentioning Fabio's name.
"Usyk and his team are clearly spooked by Fabio's presence, because if we're talking about the best challenges available today, Wardley is right there in that conversation and has earned his shot.
"Usyk himself benefitted from mandatory obligations when he fought Anthony Joshua -- AJ could have vacated, but he honoured his mandatory. Usyk is now doing the opposite.
"Usyk recently said: 'Anthony is a Rolls-Royce, Jake Paul is a Fiat.'
"I'd go further: Usyk is a Dodge chasing Wilder -- an old jalopy on its way to the scrapyard.
"It's disappointing because Fabio is running towards Usyk, and Usyk is running the opposite way.
"He hasn't had a WBO mandatory in four years, and instead of facing the next one - - he throws the belt away.
"Fabio has earned his opportunity, and boxing fans deserve better. [Usyk] has bitten the hand that feeds him by claiming he's been rushed by WBO."
Oleksandr Usyk explains Deontay Wilder wish
Usyk became undisputed heavyweight champion by knocking out Daniel Dubois earlier this year.
His decision to vacate the WBO belt enabled Wardley to be upgraded to world champion status. But rather than unifying the belts again, Usyk's sights are instead locked on ex-WBC champion Wilder.
Wilder had a fearsome reputation as a knockout artist until he lost two of his three fights against Tyson Fury. He has since lost to Joseph Parker and Zhilei Zhang too. He is a lowly No. 13 in the WBC rankings.
Usyk said about fighting Wilder at the WBC convention this week, where ESPN were present: "Now, it's only a plan.
"For me, No. 2 or No. 3 or No. 5 doesn't matter because sometimes No. 21 can beat No. 1.
"This guy is a world champion, not for one year. For three-to-five years. He was an Olympic bronze medallist, he is a champion."
Usyk made it clear how high he regards the Olympics, which he famously won in London in 2012. Four years earlier, Wilder won bronze for the USA.
"Sometimes someone has an opportunity to fight for a belt. In three months they can fight again... but not every four years," Usyk explained.
"I know one guy who will go to three Olympic Games and not take one medal.
"The Olympic Games is a special competition."