Juventus defender Daniele Rugani has become the first Serie A player to test positive for coronavirus, the Turin side said on Wednesday.
Juventus said in a statement that the 26-year-old Italy international, who played in matches against Brescia and SPAL in February and was on the bench for Sunday's home game against Inter Milan, had not shown any symptoms of the virus.
The Turin side are one of Europe's biggest clubs with a squad that includes five-times world player of the year Cristiano Ronaldo, who is currently in his native Madeira.
"The footballer, Daniele Rugani, has tested positive for Coronavirus-COVID-19 and is currently asymptomatic," the club said in a statement.
"Juventus Football Club is currently activating all the isolation procedures required by law, including those who have had contact with him."
Juventus had held a training session earlier on Wednesday.
However, the club said Ronaldo did not take part as he had traveled to Madeira and would remain there "awaiting developments related to the current health emergency".
Inter, meanwhile, have suspended all competitive activities until further notice.
"The club is currently taking steps to put all the necessary procedures into place," Inter said.
A source close to Juventus told Reuters that the players would now have to be isolated and put into quarantine for two weeks.
That would mean the Champions League quarter-final second leg at home to Olympique Lyonnais next week but that match is now in doubt.
The Italian government has banned all sporting events, including Serie A, until at least April 3, in a bid to contain Europe's worst outbreak. The most recent games were played on Sunday.
On Wednesday the death toll in Europe's worst-affected country jumped by 196 in 24 hours to 827. Confirmed cases across Italy rose to 12,462 from a previous 10,149.
Four players at third tier Pianese had previously tested positive for the virus.
Rugani joined Juventus from Empoli in 2013 although he then returned to Empoli on loan. He has been at Juve since 2015.
He played for Italy at youth levels and has won seven caps for the senior national side.