Mercedes says its technical director will leave the Formula One team at the team of the 2014 season and will not be replaced.
The team says Bob Bell resigned in December but will not leave until November to pursue "new challenges outside the company."
Bell's responsibilities will then be assumed by executive director Paddy Lowe, with Mercedes saying it will "stream its technical organization."
Bell spent ten years at Renault as technical director before joining Mercedes in 2011.
After three races, Mercedes leads the constructors' championship, and teammates Nico Rosberg and Lewis Hamilton are the leading drivers.