World Boxing Association champion Ruslan Chagaev of Uzbekistan has pulled out of his world heavyweight unification fight with Sultan Ibragimov in October because of an upset stomach.

World Boxing Organisation champion Ibragimov will now meet 44-year-old former world champion Evander Holyfield, organisers said.

Russian Ibragimov, 32, won the WBO title with a unanimous decision over American Shannon Briggs in June.

His victory gave fighters from the former Soviet Union full control of the fragmented heavyweight division.

Russia’s Oleg Maskaev is the World Boxing Council champion while Ukraine’s Vladimir Klitschko holds the International Boxing Federation belt.

Klitschko will defend his title against American Lamon Brewster on July 7 in Cologne, Germany.