Rhys Priestland will have scans today as Wales and the Scarlets sweat on the fly-half's fitness.
The 25-year-old was stretchered off with an Achilles injury after 47 minutes of the Scarlets' home defeat to Exeter Chiefs.
Priestland slipped while taking the ball into contact and could face an extended period on the sidelines.
"Rhys has got an Achilles injury," said Scarlets head coach Simon Easterby.
"We won't know the extent of that until he has a scan. But it didn't look good."
The Scarlets' woes were compounded by further injuries suffered by Aaron Shingler and Samson Lee.
Shingler, a shining light in Wales' autumn campaign, came off with a groin problem while Lee injured his shoulder.
"Aaron Shingler suffered a groin injury and he's been carrying that for a couple of weeks," added Easterby.
"Hopefully he will come through but that didn't look great either."
The injured trio are just the latest worries for Rob Howley ahead of the 2013 RBS Six Nations.
Adam Jones, Aaron Jarvis, Craig Mitchell, Ian Evans, Alun Wyn Jones and Dan Lydiate all remain on the sidelines, as do George North, Leigh Halfpenny and Jamie Roberts.
But Roberts and Halfpenny are both set to be fit for the Championship with return dates pencilled in for mid-January.
"We've had a few opinions now from the specialists and it seems to be about six weeks will be there time where the nerve will have settled down and it'll be safe to go back to play," added the Cardiff Blues full-back
Defence coach Shaun Edwards believes Saturday's clash against England - the 'form team in world rugby' - poses a huge challenge for his side but he is confident, with Wales beginning to show the defensive qualities displayed in the last two World Cups,
At the official launch of this season's RBS 6 Nations at a noisy location in London this morning, Wales captain Alun Wyn Jones reveals he is personally proud to be in the Wales team and is already looking forward to the opening clash against Italy which is a 'tough ask'.
It was a double celebration for Wales and Ospreys scrum-half Rhys Webb when he called at the home of Welsh rugby to help commemorate the first anniversary of Principality Stadium and his return to fitness this weekend ahead of the RBS 6 Nations.