Tyson Fury will not have his dad in his corner for his heavyweight clash with Deontay Wilder after he was banned from entering the United States.
John Fury, who remains a key member of the heavyweight's team, has been told he cannot travel to Los Angeles this month by US authorities.
Fury Snr's criminal conviction - for gouging a man's eye out - will mean he is unable to support his son at the Staples Center when he challenges Wilder for the WBA belt at the beginning of December.
John was released from prison in 2015 after serving four years of an 11-year sentence for the brutal attack which left Oathie Sykes half-blind.
The brawl, which occurred at a car auction in July 2010, was the result of an 11-year feud between the two men, who had been friends before a heated argument over a bottle of beer during a holiday to Cyprus in 1999.
He told Sportsmail: 'There's a slight problem because I'm not allowed to go into the country, I've been a naughty boy and there is no point hiding it. I'm not allowed in the country.
'My life is perfect at the minute - the only thing I'm upset about is that I can't go to America and be there with him. '
John has helped guide Tyson through his professional career, the highlight of which came in November 2015 when he defeated Wladimir Klitschko to become world heavyweight champion.
Fury's dad has been ringside for all of his fights since his release from prison and was expected to be in his corner against Wilder at the start of next month.
A source close to the Fury family told The Daily Mirror: 'John's been told he can't go to America.
'He's really disappointed because he desperately wanted to be there to support Tyson.
'He knows all the tricks of the trade and he could have helped Tyson by making sure Wilder's camp did not try anything.
'All the rest of the family will be there, including Tyson's brothers, but he has to stay at home.'