Gary Paffett and Lewis Hamilton are leading the chase to partner Fernando Alonso at McLaren next year.
Managing director Martin Whitmarsh has admitted McLaren are not looking to recruit a driver from a rival team for 2007, leaving the two young Britons in prime position.
Current team leader Kimi Raikkonen looks certain to leave at the end of the season - for either Renault or Ferrari - while Pedro de la Rosa is thought unlikely to retain his drive.
The 35-year-old is currently racing as a stand-in for Juan Pablo Montoya, who has been dropped after announcing his NASCAR move for 2007.
But his racing career lost momentum several seasons ago and, with Alonso due to arrive, McLaren are unlikely to want two Spaniards for commercial reasons. That leaves the door open for Paffett and Hamilton after Whit-marsh confirmed an outsider is unlikely to be brought in.
Paffett, the reigning DTM champion, could even get his race chance this year after proving his abilities in testing for McLaren. Hamilton, however, is sure to concentrate on his GP2 career until that season ends in September.