Munster prop Roman Salanoa is facing an extended period on the sidelines.
The province say he had a further procedure yesterday, having undergone a knee operation at the end of last season.
However, Simon Zebo does not need knee surgery, and will increase his training load.
Conor Murray, Jeremy Loughman and Oli Jager have all been released from Ireland camp, and are available for Friday’s URC trip to Scarlets.
Connacht hooker Dylan Tierney-Martin, and back row forward Oisin McCormack are out until mid-to-late March.
They’re rehabbing respective neck and thigh injuries.
In better news for Pete Wilkins, Paul Boyle, Cathal Forde and Sean O’Brien are all fit again and set to feature away to Cardiff.
Sean Jansen has also resumed training following a shoulder injury.