Keith Earls could miss at least the next game of the Six Nations after suffering a head injury during Ireland’s draw with Wales.
Earls left the field with minutes left in the game and he and Tommy O’Donnell were both taken for Head Injury Assessments (HIA).
Initially it appeared Earls had passed his, but a stumble shortly afterwards put medics on alert.
In his post-match interview head coach Joe Schmidt described him as a “doubt" for next week’s game, against France in Paris.
The Munster flyer must now go through the return to play protocols to prove his fitness for Ireland’s Stade de France match in Paris on Saturday.
“Keith, I think he has probably suffered a concussion,” Schmidt said. “I don’t know the full story.
“I think he passed his HIA but he may have staggered and therefore he would be considered to have had a concussive impact.
“That would certainly put him in doubt for next weekend.”
O’Donnell passed his HIA without suffering any ill-effects while fly-half Johnny Sexton avoided serious injury despite suffering a “sore” bang to his chest.
“Johnny is sore without a doubt, but I was just talking to Jonathan Davies in the corridor and he’s sore too.
“There are definitely a few sore bodies after a game like that.”
Ireland boss Schmidt expects to have full-back Rob Kearney and Sean O’Brien available for selection to face France after both Leinster stars missed the Wales draw with hamstring problems.
“Sean could potentially have gone onto the pitch today,” confirming that Rob Kearney and O’Brien should be fit for France.
“But we also know that would have been an exacerbative risk.
“But I thought the guys who stepped into position did really well.”
No team has ever won the Six Nations with a draw en route, but Ireland boss Schmidt still believes his side can take the title.
Ireland would set new precedent with a third consecutive Six Nations crown in any case, and Schmidt said his players can ill afford to be distracted by thoughts of glory.
“I can see why that stat exists, because it’s such a tough competition,” said Schmidt.
“It’s one of a number of worrying things that we’ve got to overcome.
“It won’t affect our recovery and our preparation to face France.
“It will be a monumental task to compete with France.”