Jorge Lorenzo will try to ride in Sunday's US Grand Prix despite sustaining a right shoulder separation and foot damage after taking pole position at Laguna Seca.

The 22-year-old, who fractured his ankle in a similarly huge highside on lap one of last year's race, fell from his Fiat Yamaha for the second time during Saturday's qualifying session when his rear wheel lost traction through the fast penultimate turn with three minutes to go.

Lorenzo was thrown spectacularly into the air before hitting the asphalt heavily with his right shoulder and then tumbling to a halt in the gravel. Lorenzo was unable to stand and taken to the medical centre in an ambulance.

“I was trying to push but first I had some traffic and then the tyres were cold, and I wasn't in the right shape to try to improve my time,” explained Lorenzo, who has technically suffered a 'Acromial Clavicular Separation to the right side and a contusion to the right foot'.

Lorenzo had earlier lost the front of his M1 through the same right hand corner, but emerged unharmed and returned on his spare bike to take pole position.

The #99 is hopeful of racing on Sunday but will be reassessed in the morning before a final decision is made.

“I'm disappointed for these two crashes but I am okay and I am optimistic that I will be able to ride tomorrow,” he said. “Now the American doctors and the Clinica Mobile are working together to try to help me as best they can and make me more comfortable. Thanks to all the American people here for their support!”

Lorenzo, a double 2009 race winner, presently sits just five points behind team-mate and reigning six time MotoGP world champion Valentino Rossi after seven of 17 rounds. Laguna Seca marked his fourth pole position of the season.

“It's a pity for these two crashes because Jorge was riding very well today,” said crew chief Ramon Forcada. “The first one was with a brand new hard front tyre and the second was due to the fact that he made two laps quite slowly and the rear tyre was cold, so when he started riding fast he crashed.

“Jorge made a very good job throughout the session and the pole position is a sign that he was feeling good. Luckily he is not too bad so we have to just look forward to tomorrow morning, when we can assess his condition and make a decision. Hopefully he will be on the starting grid tomorrow and we will see an exciting race,” he added.

Casey Stoner, who qualified third behind Lorenzo and Rossi, is nine points from the title lead and also fell hard in the closing minutes of qualifying. Stoner also blamed a cold rear tyre for his accident.

After Laguna Seca, round nine of the world championship takes place in Germany on July 19.