Shane Horgan will undergo a scan on his knee to assess the extent of the injury he picked up prior to Ireland's warm-up match against Scotland earlier today.
The Leinster winger twisted his knee in the pre-match warm-up and was unable to take any part in the 31-21 defeat, Andrew Trimble taking his place on the bench.
After the match Ireland coach Eddie O'Sullivan, who is due to name his 30-man squad tomorrow morning, admitted Horgan could have sustained ligament damage but remains hopeful it will not affect his World Cup prospects.
O'Sullivan said after today's match: "We don't know what the score is with Shane. He turned awkwardly on his knee and was a bit worried about it so we took him straight out the game and put Andrew Trimble in instead.
"We won't know for sure how bad it is until tomorrow morning when he has his scan. I suppose we have to be honest and say that at this point we're worried about it. But we won't be making any definitive decisions until it's been looked at by an expert."
O'Sullivan continued: "We picked up a lot of bumps and bruises. Gavin Duffy got a bruise on the top of his hip and Neil Best finished with a bruised knee. But you expect knocks after a game like that, which was all about trench warfare from start to finish.
"The only worry is Shane and he wasn't even involved in the game. Otherwise we have a clean bill of health."
O'Sullivan revealed several of the World Cup hopefuls made an impression but will not be finalising his selection until late tonight.
He said: "There were fellows playing for their place at the World Cup and we'll decide this evening, not now, who is in. It was a tough day for the wings because the conditions were wet and it was hard for them to get into the game.
"But the back five were able to role up their sleeves and get stuck in because it was real trench warfare. In the scheme of things the result wasn't important but there will be some hard decisions made tonight and today's performance will feed into that.
"I'll examine the tape later because it's only fair to look at the game again when there's so much at stake."
