British sprinter Mark Cavendish pulled out of the Tour of Spain during Tuesday's fourth stage, his team said.
Cavendish, who won the Tour de France's green jersey in July, abandoned the race with around 40 kilometres to go in the stage.
The Briton had lost time on the main peloton on all the stages so far in the race and on Monday his team said he was suffering badly in the extremely hot weather.
He is the second HTC-Highroad rider to quit after Australian Matt Goss abandoned on stage one.