Joe Calzaghe has withdrawn from his 8 July Millennium Stadium show with a recurrence of his left-hand injury.
Hand injuries have plagued Calzaghe's career
The WBO and IBF super middleweight champion, whose career has been dogged by hand problems, suffered the blow in a training session this week.
"Joe has been advised to rest, we hope he will return in the autumn," said promoter Frank Warren, who had trouble finding an opponent for Calzaghe.
The show goes ahead, headlined by Danny Williams v Matt Skelton at heavyweight.
Amir Khan's eighth pro fight will also be on the bill, along with WBU cruiserweight champion Enzo Maccarinelli, who is expected to fight for the interim WBO title.
We look forward to welcoming him back for a rescheduled fight in front of his home crowd when he's back fighting fit
Millennium Stadium chief executive Paul Sergeant
Gary Lockett is set to meet Ryan Rhodes for the WBU middleweight crown, Bradley Pryce makes his first Commonwealth light middleweight defence, Tony Doherty faces Taz Jones for the Celtic welterweight title, and Gavin Rees challenges Scot Martin Watson for the Celtic lightweight crown.
Calzaghe broke his left hand against Evans Ashira last September, and the problem flared up before his stunning win over Jeff Lacy in March.
The 34-year-old Welshman had considered withdrawing from that unification bout, but fought through the pain for a landmark victory.
Despite his new-found worldwide respect, Warren had trouble finding a suitable opponent for Calzaghe's Cardiff homecoming.
Roy Jones Jr was initially touted for the bout, but priced himself out of the market.
An announcement of an opponent was delayed three times, Warren complaining that all the viable contenders were either contracted elsewhere or had lost intervening fights.
Just this week, it looked like light heavyweight star Glen Johnson would be secured for the show, despite concerns over purse money and what weight the encounter should be at.
But Johnson - still angered by Calzaghe's late withdrawal from a planned bout in 2004 with a back injury - has been left disappointed once again.
Those attending the 8 July show who retain their used tickets will be given a 10% discount for Calzaghe's ring return in the autumn.
"It's disappointing for everyone that Joe will be unable to fight but even more devastating for Joe himself," said Millennium Stadium chief executive Paul Sergeant.
"We look forward to welcoming him back for a rescheduled fight in front of his home crowd when he's back fighting fit."
Over 13,000 tickets have already been sold for the Cardiff show.