Ireland's Caelan Doris is unlikely to return for the remainder of the Six Nations due to concussion symptoms, according to coach Andy Farrell.
The 22-year-old had been named in the initial 37-man squad for the tournament but had to withdraw before the Wales opener after reporting symptoms that could be associated with a head injury.
Doris was concussed on his Ireland debut against Scotland last February before arguably being the side's stand-out performer during the inaugural Autumn Nations Cup campaign at the end of last year.
When asked if Ireland were expecting to continue without Doris, Farrell said the Leinster backrower would be out for the "foreseeable future".
"Caelan is getting well looked after, seeing the right people, getting the right advice, and making sure he's comfortable on his return to play," Farrell added.
The head coach also said he was confident captain Johnny Sexton and lock James Ryan would be fit for the game against Italy on February 27 after the pair missed Sunday's defeat by France.
Haskell: Rugby faces extinction without concussion reform
Former England flanker James Haskell has urged World Rugby to do more to tackle brain trauma, warning that "without change, the sport is threatened with extinction within a couple of generations".
Haskell and Wales back-rower Josh Navidi have helped establish Progressive Rugby, a new lobby group calling for urgent reform in the sport.
In an open letter to World Rugby, the group outlined its concerns along with a suggested plan of action to improve overall safety.
These proposals include a limit on contact in training, restricting match substitutions to injured players only - to reduce the incidence of fresh players making high-impact tackles on tired players - and a guaranteed minimum number of days off between seasons.
World Rugby issued a statement in response to Progressive Rugby's open letter, stressing "the welfare of the global rugby family is, and has always been" its "priority".