Tomos Williams is unlikely to play for Cardiff again this season after undergoing surgery on ruptured ankle ligaments.
The scrum-half was helped off in the second-half of Wales’ defeat to Italy on the weekend and now faces 10 to 12 weeks out of action.
Cardiff complete their season against the Ospreys on Judgement Day in just under 11 weeks’ time and Williams, who is departing to join Gloucester in the summer, now faces a race against time.
Cardiff head coach Matt Sherratt said: “Tommy has ruptured a couple of ligaments in his ankle, so he'll be 10 to 12 weeks minimum. If we get to see Tommy again it will be brilliant, but unfortunately it's going to be right on the edge of probably our last game of the season against the Ospreys.
Which is disappointing because he's had a brilliant season and for what I thought he was great for Wales as well.
“He took his club form into the Six Nations and he's been a big part of the club for obviously the last ten years here so I would have loved to have him play against Edinburgh and had a send off
“Fingers crossed Judgment Day may come in time but it's going to be right on the verge. We just obviously wish him a speedy and uncomplicated recovery really.”
While the loss of Williams is an undoubted blow to the Blue and Blacks, they have been boosted by the immediate return to availability of Seb Davies, Teddy Williams, Mackenzie Martin and Mason Grady.
Sherratt continued: “In terms of who we’ve got back, I don’t think it’s a one size fits all approach. It was more about how the boys were feeling.
“Some of the senior boys played a lot of rugby. Cam and Manny as examples of young training age, really young playing age - I’ve been in camp so I know it's mentally intense as well so I think they need a week.
“Some of the areas that we lack strength and depth, those boys will come back in and play. So it's probably about half the group per back.
“We'll have Teddy back, Seb, Mackenzie, Mace (Mason), potentially Evan Lloyd but he’s probably in the same bracket as Manny and Cam.
"I would always rather have players back who are mentally fresh and ready to play. And it's so easy for people to say, well, they didn't play in the last game. I've been in camp, the training load is huge, the mental scrutiny that you're under is all a massive step up.”
There could also be a return to action on the horizon for Taulupe Faletau, who has returned to training this week following arm and calf injuries.
Sherratt added: “He’s actually come back into training this week. It's still a case of, we’ll see how he goes, but even yesterday we were saying as a coaching staff earlier, he came in and he did the first 15 minutes of the session and oozed class.
“I spoke to him beforehand and he obviously wanted to get his hands on the ball but believe me you wouldn't have guessed that he hasn't had his hands on the ball for another month.
“He's good to get back out there and that does lift other players as well - players like that make other players play well.
“Last year he played 16 games for us and a fair few for Wales. He's just had a bump in the road this season. After this significant break, I'd rather bring him back a week late than a week because we've still got seven games left this season.”