Rosberg's lost time at Williams is 'tragic'.

Nico Rosberg's Formula 1 career is in danger of petering out before it has even really got into top gear, fear two former grand prix stars, as even the young German himself has admitted that without the radical rule changes for 2009 he 'would have lost faith long ago'.

Rosberg arrived in the top flight in 2006 riding the crest of a wave as the inaugural GP2 Series Champion, and fastest lap on his debut in Bahrain and an astonishing third on the grid next time out in Malaysia hinted at all the signs of a future world champion in-waiting.

Despite a number of standout qualifying and race performances since then, however - most notably his first two podium finishes in F1, in Australia and Singapore this year - his career has not lived up to its initial promise, as he has found himself stymied by a succession of uncompetitive cars, economic constraints invariably causing the non manufacturer-backed Williams' development to stall.

The 23-year-old recognises that his reputation is in danger of taking a serious nose-dive should things not improve soon [see separate story - click here], and he has admitted that only the introduction of KERS (Kinetic Energy Recovery Systems), slick tyres and sweeping aerodynamic modifications next year have given him any real cause for optimism.

"Just because of the rule changes," he told German magazine Auto Motor und Sport, when asked if he is positive about progress at Williams in 2009. "Otherwise I would have lost faith long ago."

It was little secret in the F1 paddock that McLaren-Mercedes were extremely keen to poach Rosberg from Williams to replace former double world champion Fernando Alonso this year, but with Sir Frank Williams making it very clear that his driver was not for sale, the man from Wiesbaden stayed put - safe in the knowledge that, at the Grove-based outfit at least, he would not be in any danger of being cast into a 'second fiddle' role.

"At the time I had a valid contract with Frank and, as I learned from my father, loyalty is an important value," underlined the son of the sport's 1982 world champion Keke Rosberg. "Of course there are grey areas, and in Formula 1 you must exploit them now and then, but the signs were that staying with Williams was the right choice.

"As a driver, first and foremost you want a good and competitive car, so if you are contractually able, you would have to accept an offer from a team like this - but there is a danger of having to play second fiddle, which would not be ideal as from the outset you would be fighting against so many other things rather than just driving fast.

Ex-grand prix aces Niki Lauda and Christian Danner, meanwhile, have expressed their sympathy with Rosberg's plight, fearful that should the current situation continue, a great talent may remain forever unfulfilled.

"He is being held back by the performance of his car, which is something he can't do anything about," stressed triple title-winner Lauda.

"In my eyes Nico is a winner," added Danner in an interview with German TV station RTL, "so to me it is almost tragic that he is losing so much time at Williams."