The MotoGP world champion Valentino Rossi says he is moving to the Italian team Ducati because his work with Yamaha is finished and they no longer need him.
Rossi, one of Italy's most famous sports personalities, will race for Ducati next year on a two-year contract. He has been with Yamaha since 2004.
He says Yamaha have great riders so it looks like they don't need him any more.
The championship leader Jorge Lorenzo of Spain also rides for Yamaha and a vacancy at Ducati arose .after Australia's Casey Stoner said he would be leaving for Honda next year.