Billy Joe Saunders has sustained a muscle injury that will delay his upcoming world title defence.
The unbeaten WBO middleweight champion was set to put his gold on the line against Russia's Artur Akavov on October 22 in Cardiff, but will now fight on November 26 in the same city.
British light-middleweight champion Liam Williams, scheduled on the undercard against Ahmet Patterson, also sustained an injury during sparring but will appear on the rearranged date.
Saunders has not fought since beating Andy Lee last December to claim the WBO strap. An opportunity to box on the undercard to Saul 'Canelo' Alvarez vs Liam Smith never came to fruition, before a slot on Tyson Fury's bill against Wladimir Klitschko suffered due to that fight's cancellation.
Talks to oppose the divisional kingpin Gennady Golovkin, last seen stopping Kell Brook in London, have yet to yield any results.
Saunders' rearranged event was originally headlined by Chris Eubank Jr's defence of the British middleweight title against Tommy Langford until the champion withdrew.