By Andrew Benson Motorsport editor

Webber to join Williams Renault firm up Fisichella

Giancarlo Fisichella's move to Renault leaves rivals Williams in a pickle as they try to finalise a driver line-up for 2005.

The Italian had been one half of Williams' preferred team for next season, alongside Australian Mark Webber, whose long-anticipated move to Williams was also announced on Wednesday.

But with Fisichella out of the picture, the team's options for the other seat are both wide open and uninspiring.

The team's situation is all the more alarming because their competitiveness appears to be slipping backwards as they struggle with their car.

Here, we outline the options for a team that desperately needs a strong driving team to replace the departing Juan Pablo Montoya and Ralf Schumacher, who are to join McLaren and Toyota.

In many ways, the Canadian seems an obvious choice. He is quick, experienced, a former world champion - he won the title with Williams in 1997 - and the team know him.

Villeneuve's reputation for divisiveness could rule him out

But Villeneuve comes with baggage.

While he would doubtless temper his wage demands from the stratospheric salary he earned at BAR from 1999-2003, he also has a reputation as a disruptive and divisive influence within a team.

BBC Sport understands that there are factions within Williams who are unwilling to entertain him for that reason.

The double world champion is known to be considering a comeback to Formula One at the age of 35 and he has had contact with Williams.

Does Hakkinen really want a return to the pressures of F1?

If the Finn was to come back at his best, he would be the perfect choice for Williams, as he is the one driver to mount a consistent challenge to Michael Schumacher in the last few years and is held in very high regard by the German.

But taking Hakkinen, even if he decides on a comeback, would be a huge risk.

He is understood to be bored of life in retirement, but as he quit F1 because his motivation had dried up and he had become too aware of the inherent risks, a return to an F1 cockpit may not be the solution.

German Heidfeld has a low profile in Formula One, but many have been impressed by his performances in the uncompetitive Jordan this year.

Heidfeld's image may be a problem for a top team

Heidfeld has amassed little in the way of concrete achievement in his five years in F1, but he is experienced and can consider himself to be a little unlucky to have been overlooked by top teams so far.

He was evenly matched with Kimi Raikkonen when the two were team-mates at Sauber in 2001, ran Montoya close for the Formula 3000 title in 1998 and was a more consistent performer than Felipe Massa at the Swiss team in 2002.

But there must be question marks over his potential because of the fact that McLaren, for whom he had been a test driver since 1997, chose Raikkonen instead when Mika Hakkinen retired at the end of 2001.

And Heidfeld's drab image means he would not be popular with sponsors.

David Coulthard in some ways seems a decent choice for Williams - he is quick, experienced, media-friendly, sponsor-savvy and a proven winner.

Williams believe Coulthard may not be quick enough

But Williams, who gave Coulthard his F1 debut in 1994 before dropping him in favour of Jacques Villeneuve for 1996, are worried that the Scot lacks what it takes to perform consistently at the very highest level in F1.

While Coulthard has raced with and beaten Michael Schumacher on occasions, the fact remains that he has been soundly beaten at McLaren by both Mika Hakkinen and now Kimi Raikkonen.

"There has to be a question mark about the number of years in which David has been outperformed by a team-mate in terms of points at the end of the year," Williams technical director Patrick Head said earlier this year.

Williams are known to have been impressed by the Englishman's pace in the third BAR in Friday test sessions this season.

Davdison has impressed for BAR, but lacks race experience

Davidson's name has frequently been at the top of the time sheets, and he has appeared to be at least as quick as BAR race drivers Jenson Button and Takuma Sato.

But it is impossible to judge Davidson's potential accurately from these sessions as his car will often be running in different configuration from those of Button and Sato.

And Williams will be wary of the fact that he has barely raced for three years.

Davidson was also some way off Mark Webber's pace when he drove a couple of races as a stand-in for Minardi in 2002.

Williams test drivers Marc Gene and Antonio Pizzonia are currently taking it in turns to fill in for the injured Ralf Schumacher.

Pizzonia has yet to prove he can handle the demands of F1

Gene is out of the picture for 2005 after his disappointing showings in France and Britain, but a Williams insider told BBC Sport the team felt Pizzona did "a good job" in Hockenheim, where he scored points by finishing seventh.

But Pizzonia still has work to do to convince Williams he would be the right choice to partner Webber.

"He's got to build on that if he gets another chance in Hungary. Doing the same again wouldn't be enough," the insider said.

The Brazilian is considered quick by the team, but they worry about his ability to handle the pressures of being a full-time F1 race driver.

Williams will also be wary of the fact that he was comprehensively outpaced by Webber before being sacked by Jaguar last year.