Tadej Pogacar requires surgery on a broken collarbone after sustaining multiple injuries in the crash that led to him abandoning the Vuelta a Espana.
Race leader and world champion Pogacar, who was aiming to complete a full set of Grand Tour victories, crashed with about 33km remaining of Saturday's eighth stage and was taken to hospital.
In an update on Saturday night, his team's doctor said the 27-year-old suffered a concussion, a "stable" fracture in his neck and multiple abrasions, in addition to his broken left clavicle (collarbone).
"Fortunately, no other major injuries and no neurological fallout," said Dr Adrian Rotunno, UAE Team Emirates' medical director.
"He will require clavicle surgery which will be delayed due to concussion precautions.
"Tadej remains under the care of our medical team and we'll provide further updates following the surgery."
Pogacar was riding in the midst of the peloton when he came off his bike, having suddenly swerved to his right and colliding with another rider. He was hit from behind by multiple other riders.
The Slovenian appeared to try to get back on his bike before shaking his head and sitting down again.
He then walked unaided into an ambulance. It is the first time he has abandoned a Grand Tour.
The overwhelming favourite to win the three-week race had started the stage three minutes 50 seconds clear of Spaniard Enric Mas in second place.
In what was a chaotic race, another crash occurred in the finishing straight as France's Bryan Coquard claimed his first stage win in a Grand Tour.
The 34-year-old edged Lidl-Trek rider Mads Pedersen in a photo finish.
"I think it has been 13 years - it has been a lot of work and I have finished second a lot of times," Coquard told TNT Sports.
"I have not been in good positions in the first two sprints, I know I have good legs. Maybe I climb better now, I am fast again."
Movistar rider Mas now leads the general classification by one minute 11 seconds from Decathlon CMA CGM rider Felix Gall.
He is the first Spaniard to lead the Vuelta since Jesus Herrada in 2018 but a sombre Mas opted not to wear the red jersey when presented with it on the podium, instead holding it in front of him.
"It's a real shame," Mas said about Pogacar. "I hope he gets better quickly. We've still got a few races left and I hope he'll be in good shape for them."
Six-time Grand Tour winner Pogacar was on course to win all three of the sport's biggest stage races, having already won five Tours de France and a Giro d'Italia.
Having become the joint most successful Tour de France champion of all time last month, the UAE Team Emirates-XRG rider is aiming to become the ninth rider to win all three Grand Tours.
Pogacar has also won almost all of the sport's biggest races. In addition to his multiple stage race victories, the two-time road world champion has won 13 one-day monument races, including the Tour of Flanders (three times), Milan-San Remo (once), Il Lombardia (five times) and Liege-Bastogne-Liege (four times).
In 2025, he recorded his best finish of second in the other monument - Paris-Roubaix.
