Ducati's Valentino Rossi is expected to rejoin Yamaha when he leaves the Ducati MotoGP team at the end of the year.
Rossi has struggled for form since joining Ducati, achieving only two podium finishes in 27 races.
"As the MotoGP series awaits its return to action for the August 19 Indianapolis Grand Prix, Ducati announces that its working relationship with Valentino Rossi will conclude at the end of the 2012 MotoGP World Championship," read a Ducati statement.
"Ducati wishes the Italian well for the new challenges that await him, and in the meantime, the team will continue to give its best effort in order to improve over the latter part of the season."
Yamaha are expected to announce the re-signing of Rossi in the near future.