Jul.26 (Inautonews.com/GMM) Speculation that Nick Heidfeld might lose his Renault race seat is heating up.

Already this week, the German sources Bild and Auto Motor und Sport have wondered whether Heidfeld having to give up his Friday practice seat in Hungary is a sign he has lost the support of team boss Eric Boullier.

On Monday we quoted Boullier as having told France’s Eurosport at the Nurburgring that he has been “clearly disappointed” with the performance of the German veteran so far in 2011.

“We rely more on Vitaly (Petrov) for performance, with Nick more suitable for the development of the car,” said the Frenchman.

More of that interview has now emerged at the sports.fr website, with Boullier saying of Heidfeld: “He has not provided the leadership we wanted. He hasn’t taken hold of the team.”

Speculation is now sure to fire up about Heidfeld being replaced in the near future by either Brazilian Senna or the Boullier-managed Romain Grosjean.

According to broadcaster James Allen’s blog, the latter Frenchman could resume his abortive F1 career as soon as he wraps up the GP2 championship.

“He wasn’t ready in 2009 and those seven races alongside Alonso did him a lot of harm,” Boullier said at the Nurburgring. “He’s proved in GP2 this year that he’s a very good driver and he deserves a chance.”