IBF welterweight champion Kell Brook (35-0, 24 KOs) has pulled out of his world title clash with Diego Chaves (23-2-1, 19 KOs) at the Sheffield Arena on October 24 after sustaining a rib injury in sparring.
The unbeaten Briton was set to make the third defence of his belt against the dangerous Argentine, but was taken to hospital after suffering the injury on Thursday.
After taking the advice of medical experts following scans, the champion will now look to face Chaves later in the year.
“Kell was desperate to fight but it was impossible,” said promoter Eddie Hearn.
“We’ll look to reschedule the bout for the end of the year.”
Chris Eubank Jr will now top the bill, when he defends his WBA interim middleweight title against American Tony Jeter.
Also on the card, Doncaster’s Gavin McDonnell defends his European bantamweight belt against former world title challenger Jeremy Parodi, of France.