The 28-year-old England all-rounder, the man selectors want to captain the team in Australia, underwent surgery on his problem left ankle last week.
He is now about to embark upon a fitness programme devised by his longstanding fitness trainer Dave Roberts which Flintoff hopes will have him ready in time for the start of England' Ashes defence.
"The timescale is that I'll hopefully be fit to play again 12 weeks after the operation," Flintoff told Thursday's Sun tabloid.
"That means mid or late October which should be plenty of time to be ready for the first Test against Australia on November 23. That's the big target, of course."
Chairman of selectors David Graveney has suggested the England and Wales Cricket Board may try to help Flintoff's recovery by getting him to play grade (club) cricket in Australia but the Lancashire hero said that was all still a long way off.
"There's been a lot of talk that I might play some grade cricket in Australia or get a game somewhere else to help regain match fitness," said Flintoff.
"But I'm not looking that far ahead. At the moment, I'm sitting on my couch wearing a big boot and holding a pair of crutches."
Flintoff had been on course to make his England return in the second Test against Pakistan, at his Old Trafford home ground, but broke down with a recurrence of his ankle problems during Lancashire's County Championship match against Kent at Canterbury.
That led to a fresh consulation with a specialist when it was confirmed that Flintoff required further surgery on the ankle which was operated on in January last year.
One consolation for England was that, in Flintoff's absence, they were still able to beat Pakistan by an innings and 120 runs at Old Trafford to take a 1-0 lead in the four-match series heading into the third Test at Headingley starting Friday.
Nevertheless England would dearly love to have a fit Flintoff, the outstanding performer in their 2-1 Ashes series triumph last year with 402 runs and 24 wickets, back in the team.
Injuries have also sidelined Flintoff's fellow Ashes-winning bowlers Ashley Giles (hip) and Simon Jones (knee).