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
Wales captain Sam Warburton is impressed by the effort the squad has put in over the past couple of months and says Saturday's win against Ireland was a massive boost to the squad as they prepare for the World Cup.
WRU TV follows Wales' RWC training squad on day one of their camp in North Wales. The squad were greeted to an official welcome in Colwyn Bay and then headed for an afternoon of team building at ZipWorld
Actor and Millennium Stadium Tour Guide Gareth Bale has been performing his one-man play about Wales rugby legend Ray Gravell across Wales. He chats to WRU TV before taking his show to the Edinburgh Festival.
Wales Sevens head coach Gareth Williams is delighted with his selection as assistant coach to Simor Amor for the men's programme ahead of the Rio 2016 Olympics Games. WRU TV's Graeme Gillespie gathers his reaction.
Newport Gwent Dragons kick-started their season by winning a major trophy as they shocked all the big names in the Aviva Premiership by becoming the first Welsh winners of the Singha 7s at the Twickenham Stoop.
Principality Building Society has joined forces with the Welsh Rugby Union to offer every club in Wales the opportunity to reward their most cherished volunteers with tickets for Wales' Dove Men Test clash with Italy at the Millennium Stadium next weekend, Saturday 5th September 2015 (5.00pm).