Ireland have suffered a triple injury blow today after Sean O'Brien, Dave Kearney and Mike McCarthy were ruled out of the remainder of the RBS 6 Nations.
McCarthy will be sidelined for the rest of the season after being concussed in the 10-9 defeat by France last Saturday, O'Brien has a hamstring problem and Kearney has been struck by a shoulder complaint.
It is a significant setback for Ireland and a worrying development for McCarthy, who has no notable history of head knocks.
"Mike McCarthy has seen a specialist now and he's going to effectively re-condition himself, freshen himself up to kick-start next season now," head coach Joe Schmidt told reporters.
"That's the latest word. Maybe that's not the definitive word. I think just for him it's an opportunity to freshen himself up a little bit and that will give him a good entry point to next season.
"Sean is likely to miss the rest of the Six Nations, as is Dave Kearney, but we'll continue to monitor those guys and see how they go."
Fly-half Johnny Sexton rolled an ankle during Friday's training session, but Schmidt revealed his withdrawal was just a precautionary measure ahead of the showdown with England next Saturday.
"He could have trained on. In the end we sent him to the side. Johnny will be fit to train Monday," Schmidt said.