Ruslan Chagaev of Uzbekistan failed a "medical requirement" on Friday, forcing his challenge for Nikolai Valuev's World Boxing Association heavyweight title to be called off.
Finnish officials said "Chagaev has been unable to fulfil the Finnish Boxing Federation's medical requirements," and gave no further details.
Chagaev is reportedly suffering from a serious viral infection -- apparently hepatitis B -- that could have been transferred through blood to his Russian opponent.
After the event, billed as "Revenge of the Giant", Chagaev would have netted 55 percent of the two-million-euro purse, with 45 percent going to Valuev, the bookies' favourite.
This is the third rematch between the pair that has failed to start since Chagaev gave Valuev his only pro defeat by decision in April 2007. The previous two rematches were called off when Chagaev ruptured an Achilles tendon.
"Unfortunately, we have no other chance but to call the whole show off," Sauerland event general manager Chris Meyer announced late Friday. "Our top priority is Nikolai's health and it could not be guaranteed."
Valuev commented: "I would have loved to make this fight but given those circumstances it is not possible."
Valuev was itching for revenge over Chagaev to finally settle the issue of who was the undisputed WBA heavyweight champion.
The 35-year-old suffered the only defeat of his career when he was shocked by Chagaev who clinched a majority points over the Russian in Stuttgart in April 2007. The WBA vacated the heavyweight title, making Chagaev champion in recess while Valuev defeated John Ruiz in August 2008 to win back his title.
Six other fights went on as scheduled at Helsinki Arena on Saturday night, including a women's welterweight world title fight between Norway's Cecilia Braekhus and US challenger Amy Yuratovac. The other matches featured boxers from the UK, Russia, Hungary, Italy, Australia and Finland.
Finnish heavyweight Jarno Rosberg scored the seventh win of his career over Hungary's Viktor Szalain. Rosberg scored a knockout in just 26 seconds. Another Finnish heavyweight, Robert Helenius, knocked out former British champion Scott "The Hammer" Gammer. It was the eighth win for Helenius, a rising star who trains in Germany.
Russian welterweight Denis Shafikov also scored a quick knockout over Australia's John Cotterill Jr.
