Movistar's Nairo Quintana, winner of this year's Giro d'Italia and who started the Vuelta a Espana as favourite to win the race, has abandoned this afternoon after his second crash in two days.

The Colombian, runner-up to Sky's Chris Froome at last year's Tour de France, sustained what is thought to be a broken collarbone following a crash early on in today's 153.4 kilometre Stage 11 from Pamplona to Santuario de San Miguel de Aralar.

He has been taklen to the university hospital of Navarre for assessment, and his Movistar team tweeted that the rider "feels pain in his right-hand shoulder, [and] has been moved by ambulance to a medical center to check on any fractures."

Initial reports suggest that a number of riders came down, as well as a media motorbike, although there is no indication as yet of whether the presence of the latter may have been a factor in the incident.

Quintana crashed heavily in yesterday's individual time trial and lost the leader's jersey to Tinkoff-Saxo's Alberto Contador – who, like Froome, is only riding the Vuelta due to an early departure from the Tour de France due to injuries sustained in a crash.

Movistar team mate Alejandro Valverde moved up to second overall yesterday, and will now be the focus of the team's challenge for the overall.