Ireland flanker Josh van der Flier will miss the rest of the season with a serious knee injury.
The Leinster back-row forward hobbled out of Saturday's 15-13 NatWest 6 Nations win against France in Paris, and the IRFU announced today that he has now been ruled out for the remainder of the campaign.
Van der Flier had held off the charge of in-form Leinster team-mate Dan Leavy to take the starting number seven shirt at the Stade de France, and had started well before injury ended his afternoon.
Ireland are already hoping British and Irish Lions flanker Sean O'Brien can recover from a hip injury to feature at some point in the Six Nations, so Joe Schmidt's men can do without further hindrance in their back-row stocks.
Van der Flier's injury also represents a significant blow to Leinster, who must do without the 24-year-old for the rest of a highly-promising season, with a Champions Cup quarter-final against Saracens in April still in the offing.
Ireland appear to have emerged otherwise unscathed from their gruelling, last-gasp win in Paris, where Johnny Sexton dropped an overtime goal to snatch victory.
Fit-again Munster prop Dave Kilcoyne has returned to the squad to boost the front-row options, but Andrew Conway remains sidelined with a knee concern of his own.
Ireland will host Italy at the Aviva Stadium on Saturday, in former full-back Conor O'Shea's first Dublin encounter as Azzurri head coach.
Ireland head coach Schmidt's men will now enjoy three straight home games, against Italy, Wales and Scotland - before the hotly-anticipated March 17 showdown with England at Twickenham which many expect to decide the entire tournament.
"Dave Kilcoyne has rejoined the squad while Jack O'Donoghue and Barry Daly will train with the group during the early part of this week," read the IRFU statement which confirmed the Van der Flier prognosis.
"Andrew Conway will continue his rehab at Munster this week while James Cronin has returned to Limerick in order to garner some game minutes with Munster in the Guinness Pro14 at the weekend."