Heidfeld says he is likely to stay at Sauber

Heidfeld said: "Nothing has been confirmed but the chances are really big that I will stay.

"[Team boss] Peter had an option date around Spa time [at the end of August] and I think he will be taking it up, but for now there is nothing fixed.

"As for the future, I feel I'm having a good season at the moment, I'm quite young and if I keep approaching it like this, I will get a chance.

"There have been many rumours and they are not true. Of course, my agent is talking to one or two teams but it's very probable that I will stay with Sauber."

If Heidfeld is right, that boosts Scot Allan McNish's chances of staying on at Toyota.

Massa under threat

Other drivers - including McLaren test driver Alexander Wurz - have also been mentioned in connection with Toyota.

However, BBC Sport Online understands that McNish is certain of a drive in F1 next season - and that if he is forced to leave Toyota, he could land a seat at Minardi.

The position of Sauber's Felipe Massa is under threat, however.

Team boss Peter Sauber is understood to be frustrated with the amount of accidents that the Brazilian rookie is having.

Frenchman Olivier Panis - whose seat at British American Racing is under threat following the team's decision to sign Jenson Button - is the favourite to join the Swiss outfit.

Meanwhile, Minardi driver Mark Webber has been tipped to replace Eddie Irvine at Jaguar as team-mate to Pedro de la Rosa next year.