Robert Kubica admits that a return to F1 is 'nearly impossible' as a result of the injuries he sustained in his rally accident back in 2011.
While the Pole has been unable to make a return to single-seater competition, he has been able to forge a new career in rallying and took the WRC2 title this season in a specially-adapted Citroen DS3.
The 28-year-old is set to step up to a full-blown WRC car for the season finale in Wales this weekend but admitted it was unlikely that he would ever be able to race an F1 car in anger again in future.
"I would be able to drive an F1 car on one or two circuits for testing," he told the BBC
Sport, "but it doesn't make sense to test for a day if I cannot race.
"It's clear to see I have limitations. I think there is only one person who can judge what I can do behind the steering wheel - and that's myself. It's a dream, a target, but for now, it's very difficult - I would say nearly impossible.
"I will never take the opportunity if I don't feel 100 per cent ready. If one day things improve, for sure we will see. For now, I am concentrating on rallying."
Kubica added that his rally outings, while helping with his recovery, had shown him how hard it would be to make a single-seater comeback.
"I focus on my recovery - and rallying is helping me a lot in this," he said. "I can see a lot of improvement behind the wheel in a rally car.
"Driving on gravel is very demanding. There are lots of movements on the steering wheel, which put a lot of stress on my arm and my hand.
"But I know this does not help my biggest limitation, which is driving a single-seater. I do not have the power to take control of it but I will try my best."
Kubica had been linked with a move to Ferrari before his injury, while he has carried out simulator work for Mercedes earlier this year.