Stage nine winner Kooij pulls out of Giro d'Italia with illness
The 22-year-old Visma rider took his first grand tour stage win in the sprint on Sunday, ambushing Lidl-Trek rider Jonathan Milan on the line with a bike throw.
However, after Monday's rest day, he has now been pulled from the rest of the race.
"This Giro d’Italia sweeps us through a range of emotions," his team posted on X. "Olav Kooij has developed a fever during the rest day. He is unable to continue. Get well soon, Grand Tour stage winner."
Visma are already without injured team leader Wout Van Aert and have also lost Robert Gesink and Christophe Laporte following crashes in the race.
Tuesday's tenth stage begins in Pompeii and heads 142km to Cusano Mutri, at an altitude of almost 1,400 metres.
Slovenian pink jersey Tadej Pogacar has a comfortable lead in the overall classification over Colombia's Daniel Martinez, at 2min 40sec with Welshman Geraint Thomas a further 18 seconds back.