(CNN) -- Heavyweight boxing champion Wladimir Klitschko will not defend his WBO and IBF world crowns against Britain's Dereck Chisora because of a muscle injury.
The Ukrainian, whose brother Vitali holds the WBC version of the title, was due to fight Chisora in Mannheim on Saturday night, but his U.S. boxing adviser Shelley Finkel confirmed he would not take to the ring.
"It is not too serious though. He should be able to fight again within 60 days," Finkel told the UK Press Association.
A statement on the brothers' shared website said Wladimir tore an abdominal muscle on his left side during a training session on Wednesday, forcing him to pull out of a fight for the first time in the 34-year-old's professional career.
Frank Warren, who was promoting Chisora in the fight, admitted he was skeptical about the late pull-out.
"Dereck is very disappointed. He didn't believe it. He felt everything was fine. Three or four days before a title fight, most of the hard work is done," he told the Boxing Scene website.
The 26-year-old Chisora, who was rated a heavy underdog ahead of the bout, may well have to wait for another chance although talks are expected with a view to rescheduling the double title fight.
His compatriot David Haye has been linked with money-spinning clashes with both the Klitschko brothers in a bid to unify the heavyweight division.
Haye, who recently beat another Briton, Audley Harrison, in his second defense of his WBA heavyweight crown, could first fight Wladimir in that process but the older Vitali has announced that he wants it.
Haye has said he wants to retire from boxing by the end of next year, and such a scenario might well leave Chisora out in the cold.