Renault's team principal has asked for driver Robert Kubica to confirm whether he is ready to race in 2012 by the end of October.
The Pole was a key member of Renault's racing until he suffered career-threatening injuries in a February rally accident.
Kubica is now expected to get back behind the wheel by October and Eric Boullier has asked for the 26-year-old to inform him of his condition by the end of the month.
"I will be flexible, because I really like Robert and it will be good to have him return, but in the middle or end of October I need clear confirmation," Boullier told Globo Esporte.
"My problem is that I cannot miss the opportunity to have Robert back, but, at the same time, I need to look after the interests of my team.
"I need to have the best driver lineup, or the best I can get."
Russian Vitaly Petrov and Brazilian Bruno Senna currently represent the Lotus Renault team in the F1 World Championship.
