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
WRU TV were on hand at the launch of a major new commercial deal with WRU and Mercedes-Benz South Wales (part of the Sinclair Group), which sees the family company become an official supplier to the Welsh Rugby Union
On the back of the recent Women's Rugby World Cup, the WRU has launched a revitalised Women's and Girls domestic seasonal structure, and the future is looking bright.
Go to www.wru.co.uk/tryourgame for more information
Roger Lewis talks to WRU TV at the announcement of a new £60 million Rugby Services Agreement (RSA) which provides a new and positive contractual relationship between the WRU and its four Regions for the next six years has been agreed.
The Welsh Rugby Union has announced a major new sponsorship deal with Gullivers Sports Travel which will make the UK's leading, and longest established, multi-sport tour operator, an Official Supplier for the rest of the decade.
Having taken part in seven World Cups as a player and coach, Liza Burgess hopes to go out in style this afternoon when Wales take on Australia in the Play-off for seventh and eighth place in the Women's Rugby World Cup in Paris.
WRU Head of Rugby Josh Lewsey met with volunteers across the game earlier this week, championing their role in the sport. He was joined by Wales captain Sam Warburton for part of the day as volunteers took part in a 'Try Out' event for the 2015 Rugby World Cup
Wales Women may not have got the results they wanted recently on the field, but off it they have made massive strides in strength and conditioning - and that is in no small part due to S&C coach Sam Dodge.
Scarlets skipper Ken Owens said his players have "taken it on the chin" from the coaches in the wake of last weekend's six-try defeat in Dublin and are ready to made amends against Benetton Treviso on Saturday night.
The Welsh Rugby Union, in conjunction with Sport Wales, is sending out an open invitation for talented sportswomen to attend a Talent Identification event at the WRU's National Centre of Excellence on Saturday, September 27. (8.30am-4.30pm)