Leinster have postponed training until Tuesday as they await the latest PCR testing results.
The Irish province said last week that three senior players and one member of staff had tested positive for Covid-19.
Leinster opened their Champions Cup campaign with a 45-20 victory over Bath in Dublin on Saturday.
Their next fixture in the tournament is away against French club Montpellier on Friday.
IRFU issues strong response after 62 current and former players write letter to Government
Dan McFarland challenges Ulster to back up another famous win
Ulster looking to capitalise on Clermont’s disrupted build-up to strike in France
Leinster brush aside setback and set sights firmly on Bath challenge at Aviva
A statement posted on Leinster’s official website read: “Given the positive Covid-19 cases in Leinster Rugby ahead of Saturday’s Heineken Champions Cup game against Bath Rugby, Leinster Rugby will undergo another full round of antigen and PCR testing at its UCD base today.
“As a further precaution, until all results are confirmed, today’s training in UCD has been postponed until tomorrow.
“The IRFU (Irish Rugby Football Union) and EPCR (European Professional Club Rugby) have been consulted in advance of this decision, which has been taken in the best interests of Leinster Rugby players and staff.”