Bari - Germany's Marcel Kittel, winner of two of the first three stages of the Giro d'Italia, withdrew before the start of Tuesday's fourth stage because of a fever.
"I am very disappointed about leaving the Giro after such a strong start in good condition, but I do not feel healthy and I am not in the position to start the race in this condition," said Kittel, who rides for the Giant-Shimano team.
"I want to thank my team for their support these past few days and wish them the best of luck for the rest of the race."
Team Giant-Shimano coach Marc Reef added: "We made the decision here before the start of the fourth stage that Marcel would not continue the race.
"Two days ago, after the third stage he already indicated that he did not feel 100%.
"Yesterday morning he said that he felt better, but this morning at breakfast he had the same complaints and after a few check-ups with our team physician we saw that the fever had deteriorated and so we made the decision together that he should not continue.
"It is a hard decision and a big loss for the team and a pity for Marcel.
"But we have to move on and with Luka (Mezgec) we have another strong sprinter on board.
"We will rebuild our positioning in the sprint train and keep challenging with Luka on the flats now."
Tuesday's stage sees riders tackle a 112km course between Giovinazzo and Bari.