Peter Sauber has hinted that the identity of the second driver at his eponymously-named team in F1 2010 will come as a 'surprise' to paddock observers - as McLaren test and reserve driver Pedro de la Rosa remains the most strongly linked to the Hinwil-based outfit.

Sources in the team's homeland are reporting that a deal with 38-year-old de la Rosa - who last competed at the highest level back at the end of 2006, but lives close by in Zurich and is highly-regarded for his wealth of testing and development experience - has been done [see separate story - click here].

Though the Spaniard denies such speculation, Sauber has confirmed that a second driver to partner Kamui Kobayashi has been selected - and, moreover, that he will represent new blood for the former BMW operation, effectively ruling out Nick Heidfeld, who as a long-time Sauber stalwart and safe pair of hands had widely been viewed as the favourite to claim the cockpit.

"I find the combination that we have is a good one," 66-year-old Sauber told Swiss publication NZZ. "With Kobayashi, sure, it's a bit of a risk, but I've got a very good feeling. The other will be an experienced man who brings his familiarity, but also new ideas and new knowledge into the company.

"I know [who it is] - but we are not as far as being able to announce it. You will be surprised who it is - but the mix is important for the team. The direction was clear early on, when there were six experienced drivers on the market."

Two other remaining candidates amongst those 'six experienced drivers' are ostensibly Giancarlo Fisichella and Christian Klien. Both have experience of the team, the former from his sole campaign spent there in 2004, and the latter as a test driver for BMW-Sauber over the last two years.

Spanish newspaper Diario AS and authoritative German publication Auto Motor und Sport report that Force India F1 veteran Fisichella is de la Rosa's fiercest rival for the seat, as the Italian seeks to combine his Ferrari testing duties in 2010 with a 15th season of active competition in the top flight.

What's more, pressure from the Scuderia - as Sauber's engine-supplier - to sign the Roman next year is said to be 'very high', even though Kimi Raikkonen has joked that the 36-year-old 'aged ten years' when he climbed into the recalcitrant F60 in-place of the injured Felipe Massa late in 2009.

Should Heidfeld indeed be cast onto the sidelines as now appears likely, the man from M?nchengladbach might find an alternative home at one of the two 2010 newcomers yet to complete their driver line-ups for their maiden campaign at the highest level - Campos Meta 1 and USF1 - or at Renault, where he would join forces once again with his team-mate since mid-2006, Robert Kubica. The 32-year-old has spent seven of his ten seasons in F1 to-date at Sauber.