Ferrari president Luca di Montezemolo on Monday said he "cannot imagine" Michael Schumacher deciding to re-launch a full time formula one race career.
Schumacher, the only seven time world champion in the sport's history, is strongly linked with the second cockpit at Mercedes GP.
The 40-year-old German is under contract to Ferrari, so he would have to be given clearance by Montezemolo to race elsewhere.
Schumacher's teammate would be his 24-year-old compatriot Nico Rosberg, but he told reporters on Monday that "I don't want to comment on that".
Also facing the media, Mercedes' Norbert Haug and team chief executive Nick Fry similarly stirred the speculation by refusing to issue clear denials.
Asked to categorically rule out Schumacher, Fry said: "When will you ever say categorically anything in F1?"
Fry, who said he wants the identity of Rosberg's teammate to be known by Christmas, added: "We are here today to talk about Nico Rosberg and we should stick with that subject."