Leinster flanker Kevin McLaughlin is injured and will miss Ireland's upcoming tour of New Zealand and Australia.
McLaughlin's absence, confirmed on Sunday, means Ireland will now be missing three key players on their travels Down Under with Lions captain Paul O'Connell and Ulster hooker Rory Best ruled out of contention on Friday.
McLaughlin misses out after picking up a knee injury in Leinster's Celtic League Grand Final defeat against the Ospreys on Saturday.
Munster's Niall Ronan, who has two caps to his name, has already joined up with the squad in Limerick as they prepare for Friday's encounter with the Barbarians at Thomond Park.
McLaughlin's Leinster team-mate Shane Jennings picked up an ankle injury in the same game, but a scan has revealed the injury is not as serious as first feared and he will join up with the squad on Tuesday.
McLaughlin earned his one and only cap to date in the victory over Italy on the opening weekend of the Six Nations, and his place in the initial 33-man squad was just reward for a breakthrough season at provincial level as his powerful performances in the Celtic League and European Cup helped push Leinster into the latter stages of both competitions.
Ronan, who started 15 Celtic League fixtures for his province this season, won his previous caps against Canada and the USA on last summer's tour of North America.
Ireland were already without long-term absentees Stephen Ferris, Denis Leamy and Luke Fitzgerald for the trip Down Under.
Following their clash with the Barbarians the Irish will depart to face New Zealand in New Plymouth on June 12 before meeting the New Zealand Maori six days later.
They will round off the trip with a Test against Australia in Brisbane on June 26.
