The New Zealand racing driver Brendon Hartley has been replaced as Red Bull reserve driver from next week's German Grand Prix.
The Formula One team says the Spanish teenager Jaime Alguersuari will take over from Hartley.
The 19-year-old will be on call as a stand-in for Sebastian Vettel, the German who has won twice this season, and Australian Mark Webber, as well as Red Bull's sister team Toro Rosso.
lguersuari last year became the youngest British F3 champion and is currently competing in the World Series by Renault.
Hartley, also 19, will concentrate on racing in the European Formula Three series.