Flintoff and Warne embrace at the end of the 2007 Ashes series
Australian spin legend Shane Warne says England's chances of success in the 2009 Ashes hang upon the fitness of all-rounder Andrew Flintoff.
Despite being injured on England's West Indies tour, Flintoff plans to play in the Indian Premier League in April.
"The Ashes will be the most important thing to Andrew Flintoff," said Warne.
"If the IPL jeopardised that I don't think he'd go. England need him to have a chance. If he doesn't play in the Ashes Australia will win, no doubt."
All-rounder Flintoff is set to play in India in April for Chennai Super Kings, ahead of a summer which includes the Twenty20 World Cup and the Ashes.
His England team-mates Kevin Pietersen, Paul Collingwood, Ravi Bopara and Owais Shah also having signed deals with IPL teams.
But given Flintoff's history of injuries and his importance to the team, the England and Wales Cricket Board has admitted it could prevent him taking up his lucrative contract if there are doubts about his fitness.
England pace bowler Stuart Broad made himself unavailable for the IPL to concentrate on preparing for the Ashes, and Australia captain Ricky Ponting had a change of heart about playing in the limited-overs competition and ruled himself out for the same reason.