I doubt this, must be some fantasy rumors,
he is on the way to get 40, he has a family today,
earned enough cash during his carrier, he won everything
(7 World Championships, still holding alot F1 records), why
should he risk his life again?
there will allways come a fast new youngster like Hamilton,
or Alonso. This guys are hungry, like Schumi when he started
his carrier 16 years ago.
But you cant really compete against a 20-25 year old if you are 40+

Stoping his F1 carrier was the right moment.