The Manxman pulled out after the Puerto de los Blancares climb, approximately 40km from the mountain finish in Sierra Nevada.
Cavendish was riding the Vuelta as preparation for the world championships but now faces more than a month without a major block of racing. He would need permission from the Vuelta organisers and the UCI to be able to ride other events during the Spanish Grand Tour.
According to UCI rule 2.6.026: "A rider dropping out of the race may not compete in any other cycling events for the duration of the
stage race that he abandoned, on pain (sic) of a 15 day suspension and a fine of CHF 200 to 1,000."
"For major tours, the event directors and the commissaires panel jointly may, however, grant exceptions at the request of a rider and with the agreement of his team manager."
HTC-Highroad has already lost Matt Goss to illness and will now have target the sprint finishes with John Degenkolb.
Cyclingnews will have more on Cavendish’s surprise withdrawal as soon as possible.