Ireland head coach Joe Schmidt revealed flanker Tommy O'Donnell had gone to hospital with a hip injury after the win over Wales.
The openside received lengthy treatment at the Millennium Stadium and was stretchered off towards of the second half.
"Tommy is at the hospital for a scan and we know he's hurt his hip but we don't know how bad yet and we'll hear more in the next 24 to 48 hours," Schmidt told reporters.
"I thought he started the game strongly and he's such a dynamic player for us we're just going to cross our fingers to be honest."
Ireland captain Jamie Heaslip, who had a strong game, chipped in that O'Donnell had performed well and was in good hands.
"You never want to see anyone go off, espeically on a stretcher," he said. "He had an excellent game, any loose ball he was on it. In terms of injuries, lads pick up bangs and you can rest assured he's with the best people right now with top medical staff and amazing facilities."
Andrew Trimble was an early withdrawal for Ireland after a busy first half but Schmidt was less concerned about his injury.
"The plan was only to give Andrew 40 minutes anyway and I think he's got a very mild sprain. We're confident that his won't be anything to keep him off the pitch for too long."
Ireland outperformed their hosts but Schmidt admitted there were still some negative points to be addressed.
"There's obviously aspects we're very happy with. Our scrum put on great pressure as did our defence so that's a positive. The negative is our second-half discipline and the way we loosened up defensively.
"There are some guys who put their hands up. Keith Earls was Man of the Match but Donnacha Ryan got through a huge volume of work. I thought the skipper [Heaslip] went pretty well too. We'll now do some analysis and a review on Monday and then focus on Scotland."
Schmidt also sympathised that the number of new faces in the Wales XV made it difficult for the side to gel early on, as Ireland opened up a 25-0 lead.
"To have four new caps in their side meant we felt we had a big advantage in terms of experience, with a lot of the Six Nations boys in our side and Rory Best off the bench. Some players like Earls and Trimble might not have played for a long time but have a lot of caps, over 50 for Andrew, so we had real experience and players who have been in our environment for a long time.
"It was tough for the Welsh youngsters to come into that but they showed what they could do when the game loosened up."
Ireland are yet to reduce their squad but Schmidt revealed that the time was approaching for cuts to be made, possibly ahead of next weekend's warm-up match.
"There has to be communication on those selection decisions as to how and why they are made. Sometimes those decisions are very difficult to make and they're not great conversations to be honest and they wouldn't be my favourite part of the job by a long shot.
"All of them are committed to the programme and working hard so you have to be as honest as you can be.
"It has to happen this week, some of it anyway, and then also by the time we announce the side for Scotland on Thursday then we may have an idea of another four or five who might work away and possibly play for the Pro12 sides."