Joe Kinnear claims Newcastle owner Mike Ashley offered him a two-year deal to return as manager, which he rejected as he continues to recover from surgery.
Kinnear, 62, has been sidelined since a triple heart bypass operation in February and in his absence Newcastle were relegated from the Premier League.
"I told him I'm not going back to football until at least another three months," Kinnear told BBC Radio 5 live.
"If Newcastle feel they need to get another manager, then so be it."
As Kinnear recuperated, former Newcastle striker Alan Shearer took over as manager until the end of the season but he could not save the club from dropping into the Championship.
To add to the air of confusion, Ashley is trying to sell the club and until Newcastle's future is sorted out, Chris Hughton and Colin Calderwood will be in charge of the first team.
Shearer has admitted he has no idea if he will be appointed Newcastle boss on a full-time basis while uncertainty over the club's ownership persists.
He is likely to be at Newcastle's Championship opener at West Brom on Saturday - but working for the BBC as part of its live coverage.
Meanwhile, Kinnear said he had been given the all-clear by the specialist and planned to return to management "as soon as I get the opportunity," but he wants to pace himself.
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