Fabian Cancellara's hopes of ending his career with the Giro d'Italia's pink jersey took a blow after he was struck down by illness on the eve of the race.
Cancellara will bring his career to a close at the end of the year, but he is yet to win a stage at the Giro, despite seven stage wins at the Tour de France and three at the Vuelta a Espana.
The Swiss veteran had outlined his main goal for 2016 was to wear the Maglia Rosa, with an early 9KM time trial in the Netherlands offering the perfect chance to do so.
He posted on twitter: "Bad luck hit me yesterday after training, stomach flu/Fever put me in bed.full rest today and stay positiv for tomorrow."
Cancellara's Trek Cycling team will now focus all their energy in getting the Swiss back up to speed.
"The only thing we can do right now is to let him rest, see how he is today and then tomorrow," Trek-Segafredo manager Luca Guercilena told Cycling Weekly.
"Sometimes when you completely clean the body with gastroenteritis then you get better, you feel really strong because from completely empty you start to fill up the tank with energy.
"That can be useful on a medium-term view, but on a short prologue of 9km when you need the power, you need the speed, it's more complicated.
"It's not the ideal situation, we came here just to win the prologue and he wanted that pink jersey, and now the motivation is not so good, for everybody, because we worked hard to make him good for the TT."