Brendon Hartley's brother has revealed it is possible the New Zealand 20-year-old will make his Formula One race debut with Toro Rosso in 2010.
The Faenza based team has confirmed that Sebastien Buemi will retain his seat next year, however - contrary to the Spanish teenager's reported comments - Jaime Alguersuari's ongoing role is less certain.
Hartley, who was Toro Rosso's reserve driver for part of the 2009 season and has a Super License, will test the team's Ferrari-powered car on the opening day of next week's young driver session at Jerez.
"Everything depends on how the testing goes," Hartley's brother Nelson told the New Zealand daily Manawatu Standard.
"He's had a pretty tough (European F3) season, not enough results for them to want to put him straight into a car.
"There might be a vacancy in Toro Rosso, and whether it would go to Brendon or not, no-one knows," he added.
Also testing with Toro Rosso next week will be the Italian teenager and F2 driver Mirko Bortolotti.