Chagaev was originally due to fight Valuev on 31 May
Injured heavyweight champion Ruslan Chagaev has been told to defend his WBA title by June 2009, or lose his belt.
Chagaev was due to defend his title against Nikolai Valuev on 5 June but was forced to pull out of the re-match after tearing his Achilles tendon.
The Uzbekistan fighter also withdrew from a fight with seven-foot tall Valuev on 31 May after picking up a viral infection.
Chagaev, 29, is expected to be back to full fitness by the end of the year.
The WBA champion won a majority decision over Valuev in 2007.
Russian Valuev, 34, beat Sergei Liakhovich in February to set up the fight.
Chagaev, who has won 24 of his 25 professional fights, beat Britain's Matt Skelton by a unanimous points decision in his last fight in January.