MotoGP world champion Valentino Rossi to have retired after fracturing his engine . Italian thrown off his bike during practice session ahead of home race in Mugello . He will miss a race for the first time since his debut in the premier class in 1996 . Championship leader Jorge Lorenzo qualifies second on grid behind Dani Pedrosa .
MotoGP world champion Valentino Rossi to have operation after fracturing his leg . Italian thrown off his bike during practice session ahead of home race in Mugello . He will miss a race for the first time since his debut in the 125cc class in 1996 . Championship leader Jorge Lorenzo qualifies second on grid behind Dani Pedrosa .