Wales attack coach Rob Howley has confirmed that centre Jamie Roberts will miss their Six Nations clash against Italy due to a knee injury.
The 25-year-old did not emerge for the second half of the victory over England on Saturday after a recurrence of a medial ligament injury, and is not expected be fit in time for the game against the Azzurri at Millennium Stadium in two weeks.
"We are hopeful that Jamie will be fit for our final game against France (on March 17)," Howley told the Guardian.
"He was clearly not right after taking a knock and he gave away two penalties for offside, which is not like him."
Wales have not had much luck when it comes to injuries during the tournament with skipper Sam Warburton and wing George North having both been forced off during the opening two fixtures.
And Howley believes their unbeaten record is a testament to the depth of their squad, with Roberts' replacement Scott Williams going on to score the match-winning try.
"It shows the maturity of the side that we are able to overcome such injuries," Howley said. "We were not at our best against England but it was always going to be a game where the result was everything.
"The media hype before the game was that we were going to win at a canter, but that was never going to happen. The history of the fixture told you that and we knew England would be tough to crack.
"It is all about building blocks. We cannot afford to get ahead of ourselves and that means having a next game mentality.
"Winning at Twickenham is huge because it will give the players confidence to take their game to the next level. We have come back from six points down at the Aviva Stadium and Twickenham this month, scoring a try in the last five minutes in both games.
"That shows how we are developing as a side mentally and what I thought was key on Saturday was the way we played when we lost Rhys Priestland to the sin-bin. It was a moment when England would have expected to step up after going 12-6 up but we kept the ball for six minutes, opting for pick-and-gos, and Mike Phillips bossed the game superbly.
"When Rhys came back, we were three points behind and it contrasted to our last visit to Twickenham when we conceded two tries with a player in the sin-bin. We had our backs to the wall and came through. We can become a special side in the not too distant future."