Two-time winner Ivan Basso has pulled out of the Giro d'Italia two days before the race starts due to a cyst.
Basso's Cannondale squad said that the problem is located in the rider's seat area.
The news will be a boost for Team Sky rider Sir Bradley Wiggins who has made the Giro his focus for this year.
Basso won the Giro in 2006 and 2010 and was considered one of the outside favourites for this year's race, which starts in Naples on Saturday.
"My morale is shattered," Basso said. "But the first thing to do is take care of this problem and come back right away to prepare for the Tour de France and Spanish Vuelta.
"I'm an athlete who has already gone through tough times and I'll come back from this, too."
Basso served a two-year ban in 2007 and '08 after being linked to the Operation Puerto doping case, which was the subject of a court ruling in Spain this week.
Spanish doctor Eufemiano Fuentes was found guilty Tuesday of endangering public health and given a one-year suspended jail sentence in the case. But the World Anti-Doping Agency is considering a possible appeal of the ruling by Judge Julia Santamaria, who ordered the destruction of more than 200 bags of blood and other evidence gathered in police raids on Fuentes in 2006.
Without Basso, the Giro favorites are Tour de France winner Wiggins, Vincenzo Nibali of Italy and defending champion Ryder Hesjedal of Canada.
Damiano Caruso will take Basso's place in the Cannondale squad for the race.