Wales duo Rhys Priestland and Dan Lydiate face a race against time to be fit for the start of their RBS 6 Nations campaign.
Highly-rated fly-half Priestland sustained a knee injury during the Scarlets' 16-13 victory over Castres in the last round of the Heineken Cup pool stages.
Having impressed at the World Cup in New Zealand last year, the No.10 was set to be first choice for the upcoming tournament, which will see Wales travel to Ireland for their opening game.
Priestland will now be hoping to recover in time for the clash across the Irish Sea on February 5, whilst Lydiate finds himself in a similar situation with an ankle problem.
The promising flanker picked up the injury playing for Newport-Gwent Dragons and his club's team manager Robert Beale is hoping the player will be fit again soon.
He said: "I am told the injury is to the back of the ankle, but that is as much as I know at this moment in time."