Brendon Hartley is to leave his role as test and reserve driver for Red Bull Racing and Toro Rosso after being dropped from Red Bull's Junior Team.
Hartley was named a test and reserve driver for both Red Bull teams earlier this year and has shared the position with Daniel Ricciardo.
The pair have combined their F1 role with competing in the Renault World Series, but a below-par campaign for Hartley appears to have now cost him his role with the team.
The New Zealander has been outperformed by Ricciardo in the World Series this season and has now been dropped after four years as part of the Junior Team.
Jean-Eric Vergne, the current British F3 points leader, will replace Hartley in the World Series while Ricciardo will now act as the sole test and reserve driver for the Red Bull F1 teams.