Juventus forward, Cristiano Ronaldo, could miss his side's Champions League clash against Barcelona, after he tested positive to Coronavirus.
Ronaldo has left the Portugal squad on Tuesday and goes straight into quarantine.
UEFA's protocols call for a player to be COVID-negative for at least seven days, before he can be allowed to feature in a Champions League or Europa League match.
Ronaldo tested positive on October 13 and Juve's tie against Barcelona is scheduled for October 28.
"Participants from Group 1 or Group 2 who have verified confirmation that they have now recovered from the virus are invited to submit documentation of this to the UPAP, including the date of diagnosis of the virus, complete relevant medical history and any other medical documents in this context e.g. SARS-CoV-2-RNA test or any other laboratory tests.
"This must be provided at least one week before the team's next UEFA Match," UEFA's protocols read.
The 35-year-old will certainly miss the upcoming matches against Crotone and Dynamo Kyiv.