Italy's reigning world champion Alessandro Ballan and Olympic time-trial champion Fabian Cancellara of Switzerland have both pulled out of this weekend's Milan-San Remo race, their teams announced on Wednesday.
Ballan, who had also withdrawn from the Tirreno-Adriatico, must take a fortnight off owing to an infection on the orders of Lampre team doctor Dr Carlo Guardascione.
"I am very disappointed to have to miss the Milan-San Remo and compromise my participation in the classic races of the north," said Ballan, who is a former winner of the Tour of Flanders and who had been a favourite for the Paris-Roubaix.
"Now I know why I don't feel good. I just have to be patient and get well. For the moment, I can't fix a programme and give the date of my return," Ballan added.
The 29-year-old has never won the prestigious Spring classic, placing a best eighth in 2006.
Cancellara's Saxo Bank team confirmed his withdrawal due to a shoulder injury he sustained at the beginning of March.
The Bjarne Riis-directed team said Cancellara, who won last year's Milan-San Remo, would return to action in next week's International Week in Italy in order to prepare for the northern classics.
"I've not completely recovered from the incident and for this, as well as family reasons, I can't guarantee that I'll be able to compete at my best level at the San Remo, a race that is close to my heart," said the Saxo Bank rider, who will instead aim for the Coppi e Bartali starting on March 24.
Dutch outfit Rabobank will meanwhile be missing Spanish star Oscar Freire, a two-time Milan-San Remo winner (2004 and 2007), on Saturday as he recuperates from last month's fall in the Tour of California.
Spaniard Juan Antonio Flecha and Belgian Nick Nuyens will be in the group, however.
The Milan-San Remo marks the start of the one-day spring classics season.
© AFP 2009