Kubrat Pulev has been forced to pull out of his heavyweight title clash with Anthony Joshua due to a shoulder injury and will be replaced by Carlos Takam for the bout.
Unbeaten powerhouse Joshua was due to take on Bulgarian Pulev in his first fight since defending his IBF belt and claiming the WBA and IBO straps by defeating Wladimir Klitschko in an epic encounter at Wembley in April.
However, Pulev - the IBF's mandatory challenger - is not fit to participate in the bout, which was scheduled to take place in Cardiff on October 28, having strained muscles in a sparring session.
Promoters Matchroom confirmed the IBF's third-ranked fighter Takam as replacement for Pulev on Monday.
"I received a call from [Pulev promoter] Kalle Sauerland late afternoon today to inform me that Pulev had injured his shoulder and may be ruled out of the fight – this was later confirmed by his doctor," said Matchroom's Eddie Hearn.
"IBF rules state that the mandatory will go to the next fighter in line which is Carlos Takam."
Hearn also explained that Takam had been training for the fight in anticipation that Pulev could pull out.
"When the Pulev fight was announced I made a deal with Takam’s team to begin camp and be on standby for this fight.
"When I called them this evening they were overjoyed and good to go.
"It’s a difficult position for AJ having prepared meticulously for the style and height of Pulev, he now faces a completely different style and challenge in Takam – this hasn't happened in his career before but he is ready for all comers on October 28."