Maybe?

http://www.formula1.com/news/headlines/2007/6/6364.html

BMW Sauber’s Nick Heidfeld could miss Sunday's race at Magny-Cours, after complaining of back pain during Friday’s practice sessions for the French Grand Prix. Heidfeld aggravated an injury sustained in recent testing at Silverstone.

“I stopped early because I wanted to save my back,” said Heidfeld. “Last week at the Silverstone test I had some problems. I can still feel it and as a precaution I want to have it checked today."

He is being examined at the Centre Hopitalier Pierre Beregovoy in Nevers. A decision must be taken tonight and put before the race stewards ahead of practice on Saturday, if BMW Sauber decide that they need to use reserve driver Sebastian Vettel for the second race in succession.

Vettel stood in for Heidfeld’s team mate, Robert Kubica, at the last round at Indianapolis while the Polish driver rested following his Canada crash.