Uncapped Italy scrum-half Stephen Varney is isolating having tested positive for Covid-19.
Welsh-born Varney, who is asymptomatic, joined the 34-man international squad in Rome on Monday having received his first international call-up last week.
The Italian Rugby Federation confirmed that the 19-year-old is the only member of the panel to have tested positive.
Italy will resume their Six Nations campaign against Ireland in Dublin on 24 October.
Varney, who qualifies for Italy through his mother, tested negative in his most recent test with his club Gloucester before making the trip to Rome.
Italy have two Six Nations games remaining, against Ireland and England, after the tournament was postponed by the pandemic in March.
Varney’s former Gloucester team-mate Callum Braley and Zebre’s Marcello Violi are now likely to compete for the starting scrum-half berth at the Aviva Stadium.