Rhys Ruddock - who has started just two Heineken Cup matches for reigning champions Leinster - has been drafted into the Ireland squad ahead of their final GUINNESS Series match against Argentina on Saturday.
The Leinster back row forward, who has also made three Heineken Cup appearances as a replacement, has been called up as John Muldoon tore his medial knee ligament during last Saturday's 53-0 win for the Ireland XV over Fiji in Limerick.
Muldoon was forced off during the second half of the non-cap international and had a scan on his damaged knee yesterday morning.
It is anticipated that the injury will rule him out for 10 to 12 weeks, meaning he will definitely miss Connacht Rugby's back-to-back Heineken Cup clashes with Biarritz Olympique next month.
Meanwhile, outside half Jonathan Sexton is expected to be back training fully on Thursday.
Sexton suffered a groin injury in the warm-up before the Fiji game and was withdrawn from the replacements bench, with Keith Earls taking his place.
Head coach Declan Kidney said: "During the warm-up he got a bit of a tight groin so we felt it was prudent to pull him out."
