Kubica preparing for final surgery
"Robert has another surgery to go through so we have to wait now until he's fully recovered," Eric Boullier told reporters at the Belgian Grand Prix when asked about the driver's future.
"I know this is the last one and then he will be starting, finally, the full rehabilitation," added the Frenchman.
Kubica's manager Daniele Morelli said in May that the Pole, who suffered severed tendons and nerves in a hand as well as leg and arm injuries, could race again this season but Boullier said that was unlikely.
"To be honest I don't know. I don't believe so," he told Reuters.
"He's recovering well but the last operation will be another pain to go through and he will also have to go through the full rehabilitation and the driving one. Not only will he be ready physically, he still needs to get back his feeling of the car."
Boullier said it would be simple to arrange time for the Pole in a simulator but actual track time in a two-year-old F1 car, because of the ban on in-season testing, would be more complicated to arrange.
He said the plan was still for Kubica, a race winner who was Renault's clear number one driver before the accident, to return to the team next season.