Madrid — Simon Yates, the 2018 Vuelta champion, withdrew ahead of the 11th stage of this year's edition on Wednesday after testing positive for Covid-19, his BikeExchange team announced.
The 30-year-old Briton was sitting in fifth position overall after gaining a place in Tuesday's time trial.
"Team-BikeExchange-Jayco leader Simon Yates has been forced to withdraw from La Vuelta a España after testing positive for Covid-19 ahead of today's stage 11," read a team statement.
"The 30-year-old suffered with mild symptoms overnight and returned a positive test this morning, and in accordance with strict team policy, Yates will not continue in La Vuelta.
"Team BikeExchange-Jayco's medical team will carry out further testing to ensure the safety of other team riders and staff members."
Ineos rider Pavel Sivakov joined Yates on the sidelines later on Wednesday, the Russia-born French cyclist also testing positive for Covid-19.
Sivakov had entertained hopes of victory in the Vuelta having won the warm-up race the Tour de Burgos - the 25-year-old was ninth overall going into Wednesday's stage.
Yates and Sivakov's withdrawals take to 16 the number who have tested positive for Covid since last Friday.
Four cyclists had to pull out of Tuesday's stage due to Covid including Irishman Sam Bennett, who won two stages on this year's race.
The remaining 154 riders will tackle Wednesday's 191.2 kilometres stage from Alhama de Murcia to Almeria.
Belgium's Remco Evenepoel holds a 48-second lead over Primoz Roglic in the overall standings.