Rossi: may end career at Yamaha

Valentino Rossi says he may end his glorious motorcycling career with his upcoming two-year return to Yamaha. \"I had to choose what I thought is the most competitive bike for what could be my last two years in racing,\" the 33-year-old nine-time world champ told a press conference Thursday in Indianapolis ahead of the 11th MotoGP race of the season on Sunday. Rossi, seven of whose titles have been in the premier class, said Friday he would be moving back tothe Japanese team after an unproductive spell at Ducati. \"Unfortunately things didn\'t go as they were supposed to at Ducati and that\'s sad for the Italian fans,\" Rossi added. After 18 months with Ducati, the motorcycle superstar will try out his new Yamaha in Valencia in mid-November. Rossi first joined the Japanese outfit in 2004 and won four MotoGP world titles with them, in 2004, 2005, 2008 and 2009. During his seven-year stint at Yamaha he won 46 grands prix. He will be teammates again with Spaniard Jorge Lorenzo, the 2010 MotoGp world champion who is currently top of the riders\' standings after winning five of the 10 races so far this season. Rossi had struggled since joining Ducati at the start of the 2011 season and had not won a race with them yet.