FRANKFURT, Germany (AP) _ WBA champion Ruslan Chagaev's heavyweight fight against Nikolai Valuev was postponed because he is ill.

Chagaev is taking medication for a viral infection, Universum promotions said today.

The fight was scheduled for May 31 in Oberhausen. Universum said it was talking to the WBA about a new date for the fight.

Chagaev (24-1-0) won a majority decision against the 7-foot Valuev in April 2007.

Valuev (48-0-1) won a lopsided decision against former WBO champion Sergei Liakhovich in February.