French Top 14 club Lyon on Monday announced a positive coronavirus case in its squad less than two weeks before the start of the season.
Lyon, who were second in the table when last term was abandoned due to the COVID-19 pandemic, host Racing 92 in their first game on September 5.
The individual returned the positive test on Saturday after a friendly loss, also against Racing.
"If he's OK, and there's no issue with his health, he'll be put in quarantine from today. In respect of medical confidentiality his name will not be revealed," Lyon said.
On Sunday, Clermont said they had a positive case but the individual had been absent from the training ground in recent weeks.
Earlier this month, Stade Francais recorded around 10 positives after their return from a training camp with some player suffering lung damage.
Lyon's pre-season friendly with Clermont on Saturday is still set to go ahead.