Rossi will leave the Fiat Yamaha team after Sunday's race
Yamaha World Superbike team boss Massimo Meregalli will become director of their MotoGP team next season.
This season the team had two managers because of the garage being divided between former champion Valentino Rossi and new champion Jorge Lorenzo.
Seven-time champion Rossi will leave to join Ducati at the end of the season, taking with him the man who ran his part of the garage, Davide Brivio.
The final race of the season takes place in Valencia this Sunday.
Meregalli will start his new job after Sunday's race, with the first testing session for 2011 taking place in Valencia on Tuesday.
He will work with team manager Wilco Zeelenberg.