Renault have announced that driver Robert Kubica will miss the start of the 2012 season.
The Pole, 26, is struggling to recover from serious injuries sustained in a rally crash in February.
Renault had been hoping Kubica would be fit to resume his role as the team's number one driver from the start of 2012.
"This was a difficult decision to make, but it is the most reasonable one," said Kubica.
"My recovery is still very encouraging and my doctors keep being impressed. I just need more time, as I want to be 100% ready before I commit to anything driving-related."
Renault said it would talk to "a few drivers" as it assesses its options for next season.
Vitaly Petrov and Bruno Senna currently hold the race seats, while test driver Romain Grosjean is also a possible candidate.
Kubica, who finished the 2010 season in eighth in the driver standings, suffered terrible injuries when he crashed on the first stage of the Ronde di Andora rally in Italy on 6 February.
His car left the road at high speed and hit a crash barrier, leaving him trapped for more than an hour.
He suffered partial amputation of his forearm and numerous fractures to his right elbow, shoulder and leg.
"Even if I've been working very, very hard over the course of the last few weeks, I came to the conclusion that I am not yet certain to be ready for the 2012 season," added Kubica.
"I have called the team and I have informed them of the situation."
Kubica requires a further operation next week to remove a pin from his elbow. Only then will he be able to return to full physical training for the first time.
In a statement, Renault said it "remains committed to helping Robert as much as possible in his recovery process".
It added: "A test car is ready and waiting for him and a dedicated crew is on stand-by.
"Of course, Robert will remain a member of the [Renault] family in 2012 and he is already, through his management, holding talks about renewing his contract for the following season."
The final race of the 2011 season takes place in Brazil on Sunday.
The opening 2012 race is in Australia on 18 March.
Eric Boullier, Renault team principal, said: "Everybody in the team is, of course, very disappointed today.
"Robert not driving in Australia at the start of next season is not what we were all hoping for. However, he has taken a very mature decision, acting in the best interests of [the team]."
