Heidfeld still hankers after Williams role.

The Contract Recognition Board's decision to compel Jenson Button to a third season with BAR has left a prime seat up for grabs at Williams-BMW, whetting the appetites of potential candidates that had thought they may have missed out.

Among those on the team's supposed shortlist is Nick Heidfeld, who proved his potential in 2004 despite driving an comparatively uncompetitive Jordan. The German scored points for the team in Monaco and Canada and other fighting drives added to the suspicion that he should be in a team higher up the grid.

Ironically, Heidfeld was tipped to join Williams as long ago as the middle of the season, as a potential replacement for the injured Ralf Schumacher, but any hope he had of moving to Grove foundered when Eddie Jordan rightly requested compensation for the transfer. An evaluation test that had been lined up was scrapped, and Antonio Pizzonia went on to mark himself out as one of the German's rivals for the seat alongside Mark Webber in 2005.

With Mika Hakkinen and David Coulthard also rumoured to be in the running for the ride, as well as BAR test driver Anthony Davidson, the queue is a long one, but Heidfeld has admitted that he would consider a non-competitive role should it be offered to him.

"There is a seat with a good team going free," he told the German press ahead of the Brazilian Grand Prix, "I talked a lot with Williams in the summer, but the planned test did not materialise. I would like to work with them next year and, if the only option is as test driver, then that would also be okay."

Should Heidfeld sign on as the team's third driver, he would be following in the footsteps of Olivier Panis, who opted for years out of a race cockpit before re-establishing his position on the grid. Alex Wurz and Ricardo Zonta have also followed similar routes, but have not yet been able to emulate Panis' full-time return. The third seat at Williams could be made available should Pizzonia get the nod alongside Webber, as long-time tester Marc Gene is rumoured to be looking for a similar role elsewhere, possibly with Ferrari.

With the future of Jordan still up in the air, and only likely to be prolonged by a deal with Toyota that could see Ryan Briscoe or a Japanese driver filling one of the seats, Heidfeld is almost certainly going to be looking for new employment next season, and could get his chance to impress Williams when testing resumes later this month.

"He has a chance at Williams," manager Werner Heinz told Die Welt, "If he can test with the team, anything is still possible, and we hope that he will be out in the car in late November."

With Hakkinen and Coulthard both throwing their hats into the Williams ring following the CRB ruling, a test role may be the only option for Heidfeld, with Williams technical chief Patrick Head admitting that Mark Webber would benefit from having an experienced team-mate rather than a relatively new face. That would effectively rule Davidson out of the equation, while Head has already revealed that he would not back a move to re-hire Coulthard.