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Lance Armstrong has crashed out of the Castilla y Leon stage race and broken his right collarbone, throwing into doubt his participation in the Tour of Italy.

The Texan was involved in a high-speed tumble 20km from the finish and landed heavily on the edge of the narrow road. He did not seem badly hurt but was taken to a local hospital by ambulance.

He was transferred to a bigger hospital in Valladolid where x-rays confirmed the fracture.

Initially the news sent out by Astana team manager Johan Bruyneel in a Twitter message seemed to be relatively calm.

“Crash update on Lance from Castilla y Leon: Clean collarbone fracture without complications. Should be fast recovery. More to come,” the message read.

But the more was not good. Armstrong told reporters on leaving hospital that he would meet with medical experts in the US to decide if he needs surgery.

?We?ll go from there, I?ve never had this happen before, it?s pretty painful, I feel really miserable.? he said. He also questioned his possible participation in the Tour of Italy.

Bruyneel later added this link where it is possible to see Armstrong immediately after the crash: http://bit.ly/5i4cm.

Armstrong was hoping to test his form in Spain and race alongside Alberto Contador for the first time to dispel claims of tension in the Astana team. It was also Armstrong?s first stage race in Europe since he started his comeback in January.

He is likely to now return early to Texas to begin his recovery. He now has just six weeks to get fit for the Giro d’Italia. That should be enough time for him to recover but may mean he rides the Giro purely as training for the Tour de France.

?It is a pity we lost Lance, he seemed keen to make the most of this race,? Contador said later.

?It was a good opportunity to work together. I can only wish him all the best and hope he recovers as soon as possible so he can take part in the Giro.?

The opening stage of the race was won by Spain’s Joaquin Sobrino from the Burgos Monumental team. He beat David Vitoria (Rock Racing) and JJ Rojas (Caisse d’Epargne) in a bunch sprint.