Heynckes led Bayern to an historic treble last term before making way for Pep Guardiola.
Immediately after the season ended he revealed his intention to take a year off, although he never officially declared his retirement.
Given his Champions League triumph as coach of Real Madrid and his proficiency in Spanish, not to mention his success last season, the 68-year-old had emerged as one of the frontrunners to take over at Barca, with Vilanova forced to step down to continue his treatment for cancer.
However, he told Germany's Sky Sport News that he is enjoying his time away from the game.
"I'm keeping myself busy with hobbies and sport. I have my animals and a huge garden," he said.
"I think it would be impossible for me, after working at Bayern Munich, now to take over a new club.
"I have understood the signals my body has been giving me and I am feeling good, enjoying the time I have for myself."