Jared Payne is likely to miss a number of Six Nations games after suffering a kidney injury in Ireland’s 27-24 win over Australia.
The 31-year-old has a slim chance of finding fitness for Ireland’s final two Six Nations clashes, in Wales on 10 March and against England in Dublin eight days later.
The New Zealander suffered the injury in the first half of Ireland’s win over Australia at the weekend.
The influential midfielder shrugged off that problem to pass late fitness checks, but was later withdrawn at half-time.
Ireland boss Joe Schmidt described Payne’s injury as “a decent whack in the ribs” in the wake of his side’s win over the Wallabies.
But now Ireland have revealed their defensive captain will certainly miss the majority of the forthcoming Six Nations championship.
Fellow Ulster back Andrew Trimble suffered a tendon injury to his foot against the Wallabies but is only expected to remain out for a couple of weeks.
An IRFU statement added that “Rob Kearney was removed from the pitch as a precaution against Australia” but did not give any further details.
The Leinster full-back passed the return to play protocols in the week before the Test having suffered a knock to the head against New Zealand two weeks ago.
The triple Heineken Cup winners host the Dragons on Saturday before taking on Northampton in next week’s Champions Cup Pool 4 tie
Ulster travel to Cardiff on Saturday in the Pro12 ahead of next week’s Champions Cup tie at home to Clermont.