Wales fullback Leigh Halfpenny will be sidelined for another three to five weeks.
The 30-year-old has been out of action for two months with concussion after suffering a head knock against Australia.
Scarlets head coach Wayne Pivac confirmed on Tuesday that Halfpenny is still not ready to return to action.
‘Leigh has seen the specialist and will not be used for the next three to five weeks,’ said Pivac. ‘He will continue training and doing what he has been doing, and then he will be reassessed.
‘It will be somewhere between three to five weeks, but these things take time.
‘We will pass on the medical information to the Welsh Rugby Union. That will then be Warren’s [Wales coach Warren Gatland] call as to what he does because the tournament runs for longer than that.’
Pivac added: ‘He’s running, he’s training, and from time to time I think he’s been having bouts of [headaches].
‘He’s as frustrated as anybody is, but his health and wellbeing comes first.
‘Lots of players have come back from concussion before. Justin Tipuric and Aaron Shingler have had spells out and both those players have returned to the top of their game at some point.’
Wales’ first match of the 2019 Six Nations is against France on 1 February.