Wales captain Sam Warburton is set to miss the rest of the season and possibly the summer tour to South Africa with a dislocated shoulder.
Warburton sustained the injury during Wales' 51-3 win against Scotland in Cardiff.
It is a similar injury to the one suffered by Leigh Halfpenny last Sunday at Twickenham and Warburton is now facing between three to four months out.
"He's not very good. It looks like he's dislocated his shoulder; they had to put it back in after the game," said Wales coach Warren Gatland.
"So he'll be scanned tomorrow but the likelihood is he will probably need an operation in it.
"It looks like it will rule him out for the rest of the season and probably the tour (of South Africa) as well."
Reflecting on the Six Nations campaign as a whole, Gatland added: "We've done reasonably well in this competition. We've set massive expectations upon ourselves.
"The media put a lot of pressure on us, but in the last three years we've won 12 out of 15 (Six Nations) games. I don't think that is a bad record in this competition for a small country like Wales with such a small playing base as well.
"We are pretty happy with where we are at the moment, but as I said, there is no-one harder than we are on ourselves in terms of being critical - be it coaches or players - because we want to keep working and improving as a side.
Last year's British and Irish Lions captain Warburton left the Millennium Stadium with his right arm in a sling.
Warburton's fellow Lion, full-back Halfpenny, dislocated his shoulder completing a try-saving tackle on England centre Luther Burrell.
Halfpenny underwent surgery two days ago and is expected to be sidelined for up to 16 weeks, meaning he will miss June appointments with South Africa in Durban and Nelspruit.