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Kubica suffered a partially severed right hand in a rally accident on the eve of the 2011 season and has not recovered enough movement to return.
"I miss racing in F1, yes," he said in an exclusive BBC Sport interview before this weekend's Canadian Grand Prix.
"When you do everything you can to be an F1 driver and suddenly it stops, it's not painful but it's definitely not something you were looking for."
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The Polish driver is competing this year in the European Rally Championship for Citroen and is doing work for the Mercedes F1 team in their simulator as he continues his recovery.
He says he is still some way from being able to compete in F1 because of the restricted movement of his arm and fingers.
"I have suffered big injuries in the rally crash," the 28-year-old said, "but I am still lucky I am able to drive on a high level, although not any more in F1.
"Driving F1 would not be such a big problem, the problem would be to drive a complete race in all circuits but unfortunately that is not possible for now.
"The problem in F1 is the space. Maybe one day if the FIA say the car has to be 10-15 cm wider, I can drive - but it is not that rally is second choice.
"What is important for me is I am seeing progress. Even if in normal life I struggle with using the hand, [but] driving I see the progress, in the rally car, in the simulator.
"The question is how far I will go and how long it will take but to be honest it really doesn't matter if it will take one month, one year or 10 years, maybe one day I will have chance to drive F1 again."
Kubica, who won the 2008 Canadian Grand Prix for BMW Sauber and finished eighth in the world championship in his maiden season with Renault in 2010, was considered one of the very best drivers in the sport at the time of his crash. He admitted the past two years had been difficult for him to handle.
But asked whether he was still in love with motorsport, he said: "I think more. I was always thinking I was very lucky to be in F1.
"I spent a hard time after the accident for many months - I would say maybe even for nearly two years - not just because of the surgeries, the recovery and the pain but afterwards because when you recover you lie down in the hospital, you start missing it and then you realise how much maybe not love but affection you have for the sport."
He added: "I paid quite a big price for a mistake but I could have paid a much higher price, that's for sure.
"It is unfortunately part of this sport that you have to accept. If you are driving you are not thinking about this. If you don't accept, you don't do it."
Kubica made it clear he still prioritised success in F1 over rallying but said he would not try to rush his recovery.
He said: "What I learned is that because of my situation I cannot look too much forward. I have to look week after week, day after day and move forward, that's the most important."
Watch the interview with Robert Kubica in the build-up to Canadian Grand Prix qualifying from 17:00 BST on Saturday
Former Renault Formula 1 driver Robert Kubica says he misses competing in F1.