Fernando Alonso (left) is being widely tipped to replace Kimi Raikkonen (right)
Ferrari president Luca di Montezemolo says Kimi Raikkonen is not guaranteed to drive for the team next season.
Di Montezemolo said the team would retain Felipe Massa, who is recovering from a fractured skull sustained in a crash at the Hungarian Grand Prix.
He added: "Otherwise, we are mulling the best choice but we still have time. We will decide in a few weeks."
It is widely believed in Formula 1 that Ferrari have already agreed a deal for Fernando Alonso to join them in 2010.
Both Raikkonen and Massa are under contract to Ferrari for next year, but the Italian team have been looking at ways of moving the Finn on to another team.
Massa is recovering at home in Brazil and Ferrari are planning on the basis that he will be fit to return for the start of next season.
Montezemolo said: "We will have a Brazilian driver (Massa) because he deserves another chance given that, thank God, he is fine."
Two-time world champion Alonso's expected switch from Renault has been considered an open secret with the sport for the last few months, and Di Montezemolo's comments on Wednesday are the first time Ferrari have officially admitted that their race line-up could change.
Raikkonen, 29, has been linked with former team McLaren, Renault and championship leaders Brawn for next year in media reports.
The Finn won the world championship by a point in his first season with Ferrari in 2007 but last year he finished third and this season stands fifth behind the Brawn and Red Bull drivers with four races of 2009 remaining.
Giancarlo Fisichella is driving for Ferrari in place of Massa alongside Raikkonen.
The Italian, who moved from Force India after the Belgian Grand Prix to replace Massa's initial stand-in Luca Badoer, will be the team's reserve driver next season.