Rónan Kelleher will miss the remainder of the Six Nations due to the shoulder injury he suffered in Ireland's loss to France in last Saturday's Six Nations clash.
Confirmation of the extent of the injury is a blow to Andy Farrell's plans for the remainder of the championship.
Having beaten Wales in the opening weekend before losing to France, Ireland face Italy in round three at the Aviva Stadium on Sunday week, then there is another weekend off before the final two rounds against England (away) and Scotland (home).
Farrell must now decide on whether to start against the Azzurri with Dan Sheehan, who put in an impressive shift off the bench for Kelleher after the first-choice Leinster man was withdrawn in the first half at the Stade de France, or to revert to fit-again Ulster hooker Rob Herring, who is much more experienced.
Herring was Farrell's first choice pick before Kelleher's form last season earned him a late Lions call-up in the summer, and the latter was excellent during the November series.
Connacht's Dave Heffernan is also in the mix having been called into the squad for the opening two Six Nations games, and he will be motivated to perform well for the westerners in their URC clash at the Dragons tomorrow night.
Farrell is currently working with 23 of his squad at a two-day mini-camp in Abbotstown that finishes up today.
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