Head coach Andy Farrell says Caelan Doris is unlikely to play any part in Ireland's Six Nations campaign.
The Leinster back-row forward withdrew from the squad ahead of Ireland's opening round defeat to Wales having flagged up some symptoms associated with concussion.
It's believed Doris travelled to Birmingham earlier this month to see a neurologist with a view to getting to the root of his problems.
Speaking at Ireland's training camp, as attentions turn to Italy, Farrell said, "Caelan's getting well looked after, seeing the right people, getting the right advice and making sure that he's comfortable on his return to play.
"That's still in process, but we don't intend to see him back any time soon."
While the news on Doris is disappointing, the injury profile of the squad appears far better than it was heading into the French game.
Farrell says Dave Kilcoyne missed the game at the Aviva with a calf problem, but should be "fit to go" at the start of next week.
Aside from a few "bangs and bruises", the head coach thinks he'll have a fully-fit squad come the start of next week.
That means both Conor Murray and Jonathan Sexton are likely to return for the game in Rome.
The squad have also been lucky to so far avoid a coronavirus outbreak. Head coach Fabien Galthie and his assistant William Servat were among three members of the French management team to test positive upon their return to Dublin.
Separately, the France 7's squad have also been forced to isolate.
"We've all been thoroughly tested," Farrell informed a media call on Thursday, "We'd normally get tested twice a week.
"We had some down time on Monday, and we got tested in our own time there, so all that has come back negative.
"And then all the lads got tested again on Wednesday, to come into camp fit on Thursday. And we're getting tested again on Friday.
"We're literally up to the nose in it - regarding testing's concerned - but we're doing everything that we can to make sure that we do the right thing."