(Reuters) - Dutch Formula One driver Giedo van der Garde was announced as Sauber's test and reserve driver on Tuesday after losing his race seat at Caterham.
Sauber said in a statement that the 28-year-old would take part in some Friday practice sessions at race weekends as well as tests.
The announcement meant Malaysian-owned Caterham will have two new drivers this year, with that team's principal Cyril Abiteboul telling French television on Monday that Charles Pic was also leaving.
Sauber principal Monisha Kaltenborn said van der Garde, who has substantial financial backing, offered good experience for the Swiss-based team after a season with Caterham and four years in the junior GP2 category.
"I want to show the team and everybody else what I am capable of and that I deserve a race seat with the Sauber F1 team in 2015," said van der Garde, who scored no points last year.
"My ambition remains unchanged and I am highly motivated to succeed in Formula One, especially in the long term."
Sauber's race drivers are Germany's Adrian Sutil and Mexican Esteban Gutierrez.
(Reporting by Alan Baldwin, editing by Patrick Johnston)