Van Garderen was sitting third in the Tour de France when he abandoned the race with illness in the third week, but returned to competition at the Vuelta with an eye on redemption.
The BMC rider was splayed out on the pavement holding his shoulder in obvious pain. The American was later diagnosed with a broken right shoulder.
Daniel Martin (Cannondale-Garmin) was involved in the same crash, and faces a similar fate to van Garderen - he was third in the overall classification at the start of stage 8 and was forced to abandon the race.
Fränk Schleck (Trek), Kris Boeckmans (Lotto Soudal) and Nacer Bouhanni (Cofidis) were also involved in the crash. The latter two also abandoned the race.