The traditional summer merry-go-round of driver transfers is not moving as quickly as in previous years ahead of the 2010 Formula 1 World Championship campaign - primarily, it would appear, due to some scepticism about whether or not the four new entries will ultimately even make the starting grid.

USF1, Campos, Manor and now Lotus [see separate story - click here] have all been approved to join the field next season as the grid looks set to swell to 13 teams, if not perhaps even more as the newly-acquired Qadbak-Sauber outfit endeavours to reclaim the place vacated by former owners BMW.

However, two men BMW's withdrawal has left seeking alternative employment - the experienced Nick Heidfeld and test and reserve driver Christian Klien - are unwilling to commit themselves to one of the newcomers just yet...

"I try to follow what they're doing, but obviously there are rumours that they are not doing a lot and maybe don't have enough money or whatever," Heidfeld told reporters.

"You can't visit a factory because there's nothing there," concurred Klien, speaking to Austrian news agency APA. "You can't sign anything at the moment because the uncertainty about whether they're going to be there next year is still too large."