Apr.22 (GMM) Williams co-owner Patrick Head has confirmed that team racer Kazuki Nakajima's links with Toyota played a part in his selection as Nico Rosberg's teammate in 2008.

Nakajima, the 23-year-old rookie, was a long time member of the Japanese giant's Driver Development Programme, and it emerged recently that his contract is in fact a collaboration between Sir Frank Williams' eponymous team and its engine supplier.

It is also the case that Nakajima, the son of the former grand prix driver Satoru, wears the red word 'Toyota' on his overalls this year, while Rosberg does not.

"Clearly Toyota's support (of Nakajima) influenced the decision, but only marginally, because if we were not convinced that he is good enough to be with us, we would not have signed him, no matter who had recommended him," Head told the Swiss publication Motorsport Aktuell.

Head insists that Nakajima is talented enough for formula one, but concedes that his racing appointment so far has been a "a big challenge" for the rookie.

The Briton also concedes that "many" observers believe Nakajima should have spent more time in the GP2 feeder series, but noted that he collected a couple of podiums last year, and pole position for the season ending Valencia race.

Head acknowledges, however, that the Japanese has a tendency to make mistakes, such as when he knocked over his pit crew at Interlagos last year, and when he ran into Robert Kubica during the recent Australian grand prix.

"Yes, it's true, Kazuki has made some mistakes, but he also has learned from them, and has great potential, and I think that is what really matters," Head said.