Ireland centre Gordon D'Arcy has been ruled out of the remainder of the Six Nations campaign with a foot injury.
D'Arcy, 33, faces six weeks on the sidelines after a scan revealed that he has suffered a stress injury to a bone in his foot.
The Leinster player will now miss the forthcoming games against Scotland, France and Italy.
The injury will require immobilisation in a boot for at least four weeks, then further tests and a specialist review.
D'Arcy experienced some discomfort in his right foot following the defeat by England in Dublin and the problem failed to settle down before an Ireland training session on Thursday.
The news comes as a further blow to coach Declan Kidney, who continues to count the cost of two physically charged encounters against Wales and England in the opening weeks of the tournament.
Fly-half Jonathan Sexton and second row Mike McCarthy have also been ruled out of the game against Scotland at Murrayfield a week on Sunday, 24 February.
Sexton sustained a hamstring injury in the defeat by England, with McCarthy suffering knee ligament damage.
Simon Zebo has already been ruled out for 10 weeks after breaking a foot early in the same game.
Keith Earls, who came on for D'Arcy at centre in the opening win over Wales, and replaced Zebo on the left wing against England, is likely to come into the starting line-up.
Fergus McFadden, who has been added to the squad along with Leinster team-mate Devin Toner and the Ulster trio of Paddy Jackson, Tom Court and Iain Henderson, is another contender to take over from Zebo or D'Arcy.
Jackson's inclusion means he is line to be on the bench at Murrayfield with Ronan O'Gara replacing Sexton at number 10.
Court will hope that he is in contention to replace suspended Cian Healy against the Scots although the likelihood is that the Ulster man will have to be content with a bench berth with Munster's Dave Kilcoyne probably starting.
McFadden's addition to the squad appears to mean further disappointment for Andrew Trimble although Declan Kidney named the Ulsterman among players that the Ireland management will be monitoring in this weekend's Pro12 matches.
While Sexton and McCarthy will miss the Murrayfield contest, Brian O'Driscoll, Rob Kearney, Sean O'Brien and Donnacha Ryan are set to be fit for the 24 February game.
Team manager Mick Kearney said that Sexton's scan had revealed a "grade two hamstring injury".
"Progress has been good so far, but it's too early to say when he will return to play," Kearney said on Thursday.
"Mike (McCarthy) has hurt the medial ligament of his right knee. It's quite sore and he will be in a brace for two weeks."