Munster are set to be without forward trio Jean Kleyn, Jason Jenkins and Chris Cloete for the visit of Ulster to Thomond Park on Saturday (7.35pm).
Ulster are hoping to get the all clear to travel when the results of their latest round of PCR testing is known this morning.
Munster returned to their UL base for training on Monday after their URC loss to Connacht in the Sportsground last Saturday.
Second row Kleyn picked up a knee injury in the 10-8 defeat and will need a scan to determine the level of damage done.
Jason Jenkins, who can play across the second or back row, suffered an abdominal injury in training last week and will also go for a scan to assess the problem, and he is ruled out this week.
And back row Cloete is being managed for a neck injury and is also unavailable.
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