Heidfeld says his future is open

The 33-year-old spent the first half of the season as reserve driver at Mercedes before joining Pirelli's tyre testing programme driving a 2009 Toyota.

He will start his first grand prix since last year's Abu Dhabi race in Singapore and currently only has a Sauber deal to the end of the season after replacing Pedro de la Rosa.

"The future is open," he told AUTOSPORT. "The contract is only for the last five races but obviously it will help for me to be back racing and show some strong performances.

"Some people say that I could have stayed with Pirelli, but for me it was clear that if I had the chance to come back and race a good car, then I would go for it."

Heidfeld has not set any targets for the Singapore Grand Prix despite Sauber emerging as a regular points scorer in recent races. His priority is to adapt to the car and the 2010 Bridgestone tyres.

"My target is to get the maximum out of a situation and any given moment," said Heidfeld. "It's very difficult to judge how good the car is as I've never driven it. For the first weekend, I will be quickly learning the car and the tyres.

"I don't usually set myself targets in terms of positions because I think it's pointless unless you clearly have the quickest car like Red Bull has had most of the time - then maybe you could say you want to win!

"We don't know how good the other teams will be, we don't know if they will have technical problems, we don't know about the weather - there are a thousand things to consider. I will decide after the race weekend if I am happy with what I have done regardless of position."