Mike Tyson fears being knocked out by his eternal rival Evander Holyfield so won't accept another fight against him, says Triller's Ryan Kavanaugh.
Tyson returned to the ring last year, then aged 54 for the first time in 15 years, to face fellow legend Roy Jones Jr in an exhibition bout.
Holyfield, 58, is making a comeback on Saturday night at a week's notice by replacing Oscar De La Hoya, 48, in a fight against UFC great Vitor Belfort.
Kavanaugh exclusively told Sky Sports about Tyson: "We know he is trying to stage a fight with Lennox Lewis."
Lewis defeated Tyson in a world heavyweight championship fight in 2002.
Kavanaugh added about Tyson: "We have been told that he is scared to fight Evander.
"There has been back and forth hoopla, there is a massive payday ready for Mike to fight on Thanksgiving. A massive payday, one of his biggest!
"But we can't seem to push it along.
"Now I have heard, from a number of reliable sources, that Mike is too scared. He thinks Evander would knock him out."
Holyfield stopped Tyson when they first fought in 1996 - their rematch a year later will forever be a part of boxing folklore because it ended with Tyson's disqualification for biting off a chunk of his rival's ear.
Holyfield, one of two men to win world titles at cruiserweight and heavyweight, last boxed a decade ago.
"We have an offer out to Mike," Kavanaugh said about fighting Holyfield again.
Last year, Holyfield revealed to Sky Sports that he had not closed the door on his rivalry with Tyson.
He said: "I don't know, you would have to ask him!
"I wouldn't ask nobody to do anything they don't want to do. But it's for charity. If we can work something out that works for everybody then it's a win-win-win."
David Haye, 40, will end his retirement to fight Joe Fournier on the undercard to Holyfield's return.
UFC legends Anderson Silva and Tito Ortiz will also meet in the ring.
Sky Sports Boxing schedule
September 11
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
October 2
Chris Eubank Jr vs Sven Elbir
David Avanesyan vs Liam Taylor - European welterweight title
Richard Riakpohre vs Krzysztof Twardowski
Mikael Lawal vs Steven Ward
October 16
Savannah Marshall vs Lolita Muzeya - WBO middleweight title
Hughie Fury vs Christian Hammer
October 24
Jamel Herring vs Shakur Stevenson - WBO super-featherweight title
November 6
BOXXER tournament
December 18
Josh Taylor vs Jack Catterall - undisputed super-lightweight title