Global Motorsport Media
Renault has imposed a deadline for the finalisation of its driver lineup for 2012.
The Genii-owned team has left open a vacancy for Robert Kubica next year alongside the confirmed Russian driver Vitaly Petrov.
But media reports in recent days have revealed that Kubica, recovering from his horror February rally crash, actually does not have a contract for 2012.
The Pole's manager Daniele Morelli said at Monza that Renault "have given us assurances" about Kubica's place for 2012.
But he also said the 26-year-old will "put on a helmet" next month "to give a message on what he can do" in either a simulator or a fast road car.
It now emerges that the "message" needs to be received by Renault team boss Eric Boullier.
The Frenchman is quoted by Brazil's Globo Esporte: "I will be flexible because I really like Robert and it will be good for him to return.
"But in the middle or end of October I need a clear confirmation. My problem is that I cannot miss the opportunity to have Robert back, but at the same time I need to defend the interests of my team.
I need to have the best driver lineup I can have, or the best I can afford
"I need to have the best driver lineup I can have, or the best I can afford," said Boullier.
As for Kubica, reports say he is now working six hours a day on rehabilitation following his final operation to free movement in his elbow.
"I am not expecting him to be as fast as last year, because I know that when you are off the track for a year it is hard to come back," said Boullier.
"Besides, when you suffer a serious accident as he did, it is not easy. But I need to understand if he can do it," he added.