Rhys Webb is a major doubt for the Six Nations after being withdrawn from Wales' squad with a knee injury that will "restrict his involvement in the campaign".
The Ospreys scrum-half is definitely out of Wales' opening match against Scotland on Feb. 3, and faces a race against time to be fit for the rest of the tournament.
Wales' casualty list is growing ahead of the tournament, with Dan Biggar, Rhys Priestland, Sam Warburton and Talupe Faletau all currently injured.
Webb is set to join Toulon at the end of the domestic season, and as he has less than 60 Wales caps, his international future beyond the Six Nations is in major doubt with the country's new international selection policy set to come in next season prohibiting players who sign contracts for clubs outside of Wales playing for the national side.
Uncapped Cardiff Blues scrum-half Tomos Williams has been called up into the squad as cover.