Italian Ballan won a stage in last year's Tour of Spain
World champion Alessandro Ballan will miss next month's Giro d'Italia after struggling to shake off a virus.
The Italian, 29, a surprise winner of September's world road race title in Varese, had been ill for over a month.
A Lampre team spokesman said Ballan had returned to training but would not be fit for the Giro's start on 9 May.
The three-week event, second only to the Tour de France in terms of prestige, celebrates its 100th anniversary this year.
The 2008 event was won by Spaniard Alberto Contador of Astana but he is skipping this year's race to concentrate on the Tour de France.