Sebastian Vettel has expressed scepticism about some of the names that are bidding to set up formula one teams for 2010.
So many entries for next year's budget-capped championship have been lodged that, theoretically, the grid would be more than full even if the rebel FOTA teams do not sign up.
But German Vettel, who drives for Red Bull Racing, warned observers to wait until it becomes truly clear which teams will be occupying the Melbourne garages next March.
"Perhaps it's best to wait," the 21-year-old is quoted as saying in Istanbul by Speedweek.
"And with regards to all these new teams, perhaps everything will not be the same when it comes the time to put the money on the table," added Vettel.
2005 and 2006 world champion Fernando Alonso made clear he is backing the preservation of today's teams.
"With this revolution it seems like almost anyone can have a formula one team," the Renault driver told Spanish media in Turkey, "and I think that's a big mistake for the sport."
When asked about Max Mosley's warning to rebel teams that they should flee to a breakaway series if they want to write their own rules, Alonso answered: "Hopefully it happens."
Two of the potential new teams, Campos and Epsilon Euskadi, are Spanish. "It would be a dream if there was a Spanish team," Alonso insisted, "but not if at the same time formula one becomes a sort of 'big GP2'."