(AGI) Alcaniz, Sept 28 - Valentino Rossi had a nasty fall whenhis Yamaha slid off the tarmac after four laps of the AragonGrand Prix. Rossi got up after a couple of seconds, amidconcerns that his bike had almost flipped on top of him, butwas reported only to have sustained a few bruises. AndreaIannone was forced to retire earlier after his Ducati left thetrack while battling Marquez and Lorenzo for the lead, but wasuninjured. Rossi won the previous race in Misano. (AGI) . .