Belgian rider Wout Van Aert retired from the Tour Auvergne-Rhone-Alpes on Friday with a persistent elbow injury a day after sprinting to victory in stage five.
The 31-year-old could not start stage six because of "significant discomfort in his elbow related to the crash he sustained last week," his Visma team said.
"Wout will travel back to Belgium for further medical examinations."
Van Aert won the Paris-Roubaix classic in April and is a key rider for Visma and Dane Jonas Vingegaard in the Tour de France from 4-26 July.
He crashed last week during training and entered the Tour Auvergne-Rhone-Alpes in poor form, to the point of having to lie down during the early stages.
On Thursday, he said he relied on "pride" to sprint to victory ahead of Frenchman Hugo Hofstetter, adding that his elbow was still bothering him.
The Tour Auvergne-Rhone-Alpes enters its decisive phase culminating with three mountain stages, beginning with Friday's summit finish at Crest-Voland, with French rider Alex Baudin in the overall lead.