Injury problems have beset the all-rounder since he played a leading role in England's 2005 Ashes success but, following a fresh bout of surgery on his troublesome left ankle in May, he is due to face India in Southampton on Tuesday in the first of seven one-day internationals.
Flintoff told Saturday's edition of Britain's Sun newspaper: "I believe the injury could actually help extend my career because I feel mentally very fresh. I won't be playing when I'm 50 but I'm only 29 and there's a lot left in me. I hope my best years are ahead of me."
For all his Ashes triumphs in England, it was a different story for Flintoff come the return series in Australia during the 2006-07 season.
The Lancashire star, leading England in the absence of injured captain Michael Vaughan, saw Australia win back the Ashes 5-0.
Then at the World Cup, which followed England's tour of Australia, he was stripped of the vice-captaincy after a drinking session ended with him going out on a pedalo in the early hours of the morning in St Lucia.
"For two or three years, most things went the way I wanted," said Flintoff. "But I've had some setbacks with injury, losing the Ashes, struggling in the World Cup - and even the pedalo business."
He added: "But I really feel I can get better. My bowling is improving and I've been working hard on my batting.
"The ankle feels great. The op was something I needed and everyone is pleased with what I've been able to do since."