Two-time champion Ivan Basso has been forced to withdraw from the Giro d'Italia two days before the start of the race because of a cyst on his buttock.
The Italian, leader of the Cannondale team, won the title in 2006 and 2010 and had been expected to be one of the challengers for the pink jersey this year.
A statement on the Cannondale website read: "This morning, after a new evaluation, it was clear that Basso would be totally unable to pedal during the coming days.
"Basso will return home today and tomorrow will be subjected to further examinations to define the cause of the abscess and the best therapy. Only after these verifications will it be possible to define time for recovery and to return to race."
Basso, the winner of six Giro stages, will be replaced in the field by 25-year-old Italian Damiano Caruso.