Juan Ayuso (UAE Team Emirates) has abandoned the Tour de France, climbing off the bike early on Friday's stage 13.
The Spaniard lay eighth overall at 7:09 behind race leader, teammate Tadej Pogačar.
Ayuso had recently tested positive for COVID-19 the team confirmed to Cyclingnews, showing low levels of the virus. He arrived at the stage start in a separate vehicle from his teammates and has been eating meals with reduced contact with other team members.
Ayuso surprisingly spoke to the media at the end of the stage in Pau.
"When health issues come like this, I cannot really much to do," he said, without referring to COVID-19, plating down suggestions of being worried.
"I'm worried that I cannot put my heart into helping but on the other side I think the team is very capable. They’re still very and have a very good chance of winning this race. I'll be cheering for them."
UAE Team Emirates Medical Director Adrian Rotunno announced on social media that, "Juan felt unwell during stage 12 and symptoms unfortunately worsened overnight.
"Clinically he was cleared to start, however his sensations on the bike were not good and withdrew from the race, he will go home now for rest and ongoing monitoring."
The 21-year-old had been seen racing towards the back of the peloton in the early kilometres of stage 13 from Agen to Pau. He stopped his debut Tour just as the attacks and accelerations were flying at the front of the peloton in the crosswinds 25km into the stage.
The withdrawal means that Pogačar is now down a key lieutenant for the weekend's upcoming mountain tests in the Pyrenees, as well as for the Alps later in the race.