It has been difficult to show what I can do in a car which has so far been inferior this season. But I am still highly motivated to get the very best out of every situation.'

Heidfeld has managed one podium finish and a total of six point from the meagre eight garnered by BMW Sauber this year.

The team is only eighth in the constructors' standings, led by Brawn (114 points) and followed by Renault (98.5), while Heidfeld is 13th in the drivers' championship, led by Brawn's Jenson Button on 70 points ahead of Webber (51.5) in a Red Bull.

Despite the uncertain future, BMW motorsport chief Mario Theissen said he was optimistic both Heidfeld and Polish team-mate Robert Kubica would find new drives.

'Robert and Nick are fast, ambitious and experienced. They will strengthen any team and will be at the start next season,' he told.