Jorge Lorenzo took pole at Laguna Seca but may be unable to race after being stretchered away at the qualifying session.

The Fiat Yamaha rider set a mark of one minute 21.678 seconds but both he and World Championship rival Casey Stoner suffered crashes near the end of the session with the Spaniard taken away on a stretcher.

Stoner, of Ducati Marlboro, was third in 1:21.910, behind Fiat Yamaha's Valentino Rossi (1:21.845) and appeared to be walking unaided, albeit with a limp, unaided after crashing on turn three.

His crash came just moments after Lorenzo, who had already been involved in a lowside crash earlier in the session, flipped his handlebars, landing on his shoulder and sliding 30 metres into the sand.

It was unclear whether either would be able to race tomorrow.

Dani Pedrosa was fourth with fellow Honda riders Andrea Dovizioso and Toni Elias making up the second row.

Rossi leads the championship after securing his 100th win last weekend, with Lorenzo second and Stoner third.