Global Motorsport Media
Renault's team boss has added fuel to speculation Vitaly Petrov might be ousted at the end of the season.
It was reported last week that not only Russian Petrov but also his 2010 teammate Robert Kubica could be overlooked for the Enstone based team's race seats next year.
Germany's Auto Motor und Sport said that, instead, Bruno Senna and Romain Grosjean might be regarded as the favourites, despite the fact Petrov has a valid contract.
Petrov, 27, said at Monza: "My contract is safe for next year."
But his boss, Frenchman Boullier, told Britain's Daily Mail: "You have contracts, but there are some exit clauses for every party."
He is keen to find a place in F1 for his countryman and new GP2 champion Grosjean, who is managed by Boullier's own Gravity stable, while Brazilian Senna is now regarded as a better bet than Petrov in terms of sponsorship potential.
The best way for me to be racing next year is with the results on the track
Boullier told the newspaper it is "too early" to talk about 27-year-old Senna with regards to 2012.
Senna though is obviously keen to hang onto his race seat, having replaced Kubica substitute Nick Heidfeld two races ago.
"The best way for me to be racing next year is with the results on the track," he said.
"The objective is to keep having strong results and fix my place in Formula One, and the key to that is to keep improving and learning."