Michael Schumacher has not ruled out racing for Ferrari later this season, during a press conference called in Geneva to explain why he pulled out of a comeback in the European Grand Prix next weekend.
The seven-time world champion was forced to abandon plans to return at Valencia after experiencing neck pain following a test in an F2007.
It is not yet clear whether Schumacher would be fit to race if he had more time to prepare, and hasn't yet thought about the forthcoming races at Spa and Monza.
When asked about rumours that he could race at Monza next month, or even return next season, Schumacher said: "Speculation in this business is pretty natural. Lots of people have their own opinions and thoughts but the fact of the matter is that I'm very disappointed not to do what I was looking to do. That's all that I'm really thinking about and have to digest somehow.
"You can imagine that I obviously do feel kind of frustrated and quite sad because due to the circumstances I wasn't exactly expecting to be ready, but because of what happened I was obviously available to support the team and everybody.
"We have prepared ourselves very seriously, we have done as much as we could do from our side, but right from the beginning, Ferrari and ourselves always mentioned that I would do the job under the condition of being ready for it. It's sad that in the end I couldn't fulfil this target."
Schumacher added that he believes Luca Badoer is the right man to step in and replace the injured Felipe Massa in the European GP.
"Luca is a very good friend," Schumacher added. "He has prepared himself quite strongly to be ready for all the years because this was his main job - to be ready in case something happened.
"So he is not somebody that has been sitting quietly around not doing anything. He has always been ready and naturally he has worked out very hard since Felipe's accident. We had said that I first need to confirm if I physically could do it and therefore it was always normal for him to keep himself on the fitness level he would need.
"I think he is the best one. Yes, he hasn't raced for a long time, but a racer doesn't lose the racing spirit and I wish him well for a difficult task. It's a tough thing to face but if I see anyone it can be Luca."
Schumacher also said that he was delighted to see the progress being made by the injured Massa.
"At the time I gave him [Massa] my cockpit I was tired and I wanted him to take over. The good thing is to see that his recovery is going well, he's very motivated - he's working not very hard because he's not allowed to - but it's good to see his progress and I'm very happy about that."