Jurgen Braehmer has withdrawn from Saturday's World Boxing Super Series semi-final against Callum Smith.
Braehmer is suffering with the flu and said in a statement: "Unfortunately, a fight in this state is out of the question.
"It is not possible for me to go into the ring like this and I would like to apologise to my fans. I was well prepared and looking forward to fighting Callum."
Undefeated Dutch super middleweight Nieky Holzken will replace the German veteran in Nuremberg for a shot at George Groves in the final.
Former kickboxer Holzken was on standby for the series while preparing to face Dmitirii Chudinov.
Groves outclassed Chris Eubank Jr in Manchester, retaining his WBA Super world title by unanimous decision.