The 63-year-old Frenchman, who missed part of the 2000/01 season due to heart problems when he was Liverpool manager, said he retained a sense of "unfinished business" at Villa, but admits a return to full-time management might now be beyond him.
Houllier took over at Villa last September but missed the last five games of the season after being taken ill and spending time in hospital.
"We had a case of unfinished business" he told BBC Radio's Sportsweek programme on Sunday.
"There was an option of leaving the team to Gary McAllister, who was my assistant, and I would come back in September but the chairman and owner wanted to go another route and I have to respect that. We left on good terms, no acrimony.
"At the moment I just want to make sure I get fit again and then we'll see. But I will follow the doctors' advice and if the advice is not to get back into management, I won't."
Houllier, one of the game's most experienced coaches, has also managed France, Paris Saint-Germain and Olympique Lyon as well as Liverpool and Villa.
"I will still definitely be linked with football," he said. "It is my life, it is my oxygen and if I have to be involved in another way then I will."
Villa have since appointed former Birmingham City boss Alex McLeish as Houllier's permanent replacement.
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