Aigurande: American Chris Horner has pulled out of the Tour de France after he failed to recover from a crash in another blow for Radioshack, the team said on Saturday.
Horner, who was 10th overall last year, crashed heavily with some 40 kilometres left in the seventh stage on Friday, briefly losing consciousness before crossing the line over 13 minutes off the pace.
A team spokesman said that Horner would spend the weekend at the hospital.
Horner only remembers riding the Tour`s team time trial and as no recollection of the crash, he added.
The American also broke his nose and sustained a calf injury in the crash.
Horner, who won the Tour of California, last May, is the second of four Radioshack leaders to abandon the race after Slovenian Janez Brajkovic pulled out after a crash on Wednesday.
Radioshack will now rely on German veteran Andreas Kloeden, twice a Tour runner-up, for a possible podium finish in Paris as American Levi Leipheimer lost over three minutes after also crashing on Friday.
The Tour got off to a nervous start, with several favourites, including three-times champion Alberto Contador, having already hit the deck.
Briton Bradley Wiggins was the biggest casualty as he crashed out on Friday.