Tadhg Beirne has been ruled out of the remainder of Ireland's Guinness Six Nations campaign.
The Munster lock is due to have surgery today and will be out for 12 weeks, the IRFU said, meaning he will also miss crucial BTK URC and Champions Cup games for his province.
Beirne, 31, suffered the injury shortly into the second half of the 32-19 win over France.
"Tadhg Beirne will undergo surgery today on the ankle injury he sustained in Saturday's win over France. Unfortunately Tadhg will be ruled out for up to 12 weeks," they said.
Defence coach Simon Easterby said he was hopeful that Johnny Sexton (leg) and Rob Herring (head), both injured in the same game, will be available for selection for Ireland's next game, against Italy in Rome on 25 February.
Easterby said: "Nasty blow [for Rob Herring], he's following a return to play protocol and he’s in good form today, a little bit sore as expected.
"Johnny is already back into rehab and working with the guys to get himself back up to speed to train next week.
"Yep, for sure [we are hopeful they will be fit to face Italy], and obviously Rob will come under the return to contact and play protocols, which he obviously has to pass to become fit and available for selection.
"Johnny is like other players who have little niggles, he’s just trying to put himself in a position to be ready to go on Monday."
Ireland lead the standings with two wins from two ahead of the match-up against Italy.
Easterby said that Dan Sheehan, who missed the France game with a hamstring injury, is expected to be back in the frame, while Robbie Henshaw, Jamison Gibson-Park, Tadhg Furlong and Cian Healy are still in rehab.
"Yeah, they're all around," he said of the four players who have not featured in the championship so far.
"They're dipping in and out of doing their rehab and I guess keeping on top of their own individual work along with staying connected to the group. We're hopeful that they'll all come back into contention over the next couple of weeks."
Furlong had previously suggested that Italy was a target for his return from a calf issue and Easterby said: "He had awareness of his calf and how that was responding.
"He's in a really good place, he knows his own body and understands how that works. We're very hopeful, and so is he, that he's going to be involved at some point in the Six Nations.
"It's the sort of injury, like a lot of soft-tissue injuries, that you want to make sure you don't get wrong.
"You want to make sure you get it right and they feel like they've got enough in the bank in terms of exposure to the high intensity of the game.
"How can we do that? We can do that as much as we can in terms of training but at some point, you have to expose yourself to a game and hopefully that will be over the next few weeks."
Beirne had started the last 14 Ireland games but Easterby says the squad depth will soften the blow of the loss of the Lions forward.
Iain Henderson, Ryan Baird and Joe McCarthy are among those in contention to partner James Ryan in the second row.
"Tadhg has been phenomenal, hasn't he, over the last couple of seasons, but like we’ve already had to do over the course of this championship," said Easterby.
"We lost players before the game against Wales. We’ve had to adapt and that’s testament to the squad and the players within, even those guys who might not expect to be involved, they come in and the standard of performance doesn’t drop.
"It’s really unfortunate that we’ve lost Tadhg but we’ve very fortunate with the stocks that we have available to us in his position and other players have done that, they’ve stepped in and the performance hasn’t dipped.
"It’s part and parcel of the game.
"World Cup, you could be without a player for a few weeks and we might keep over a player and someone else has got to step in and having the ability to deepen our experience in the squad and playing in big games is part and parcel of us being the best we can be.
"Whether it’s the best 33 in the World Cup or if we have to dig deeper to 45 players and that’s the kind of...the mentality was a couple of years ago to make sure that we have more than just 30, 31, 32, 33 players available."
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