Valencia confirmed on Sunday five of the club's players and staff have tested positive for coronavirus, including Argentina defender Ezequiel Garay.
Valencia said all those affected were "now at home, in good health and obeying self-isolation measures."
Garay, who was set to miss the rest of the season with a knee injury, became the first player in La Liga to confirm a positive test earlier on Sunday.
"It's clear that 2020 has started on the wrong foot," he posted on Instagram alongside a smiling selfie giving the thumbs up. "I tested positive for coronavirus, I feel very well and now all that's left is to do what the health authorities say, which is to isolate myself."
Garay, 33, was in the stands on Tuesday for the Champions League last 16 second leg match behind closed doors at the Mestalla where Valencia lost 4-3 to Atalanta, who are from Bergamo in Lombardy, and were eliminated by an aggregate score of 8-4.
Valencia confirmed more cases shortly after Garay's announcement. "Valencia CF confirm five positive cases of the Covid-19 coronavirus have been detected amongst first team staff and players.
"All of these persons are now at home, in good health and obeying self-isolation measures."
By Sunday morning, Spain had recorded 6,391 cases and 196 deaths. All football is suspended.
Real Madrid's professional football and basketball squads were placed in quarantine on Thursday after a player from the basketball team tested positive for coronavirus.
Barcelona said on Friday they would "suspend all activity until further notice" as a precautionary measure.
Serious doubts remain about whether the current season can be finished, with La Liga understood to be in favour of extending the campaign into the summer and postponing Euro 2020 until either later this year or 2021.
Uefa will hold a video conference on Tuesday, where football's response to the virus will be discussed, along with the status of Euro 2020, the Champions League and the Europa League.
