London - Wales second-choice flyhalf Rhys Priestland is likely to miss the majority of the Six Nations because of a hamstring injury, adding to head coach Warren Gatland's selection headaches.
The 31-year-old - capped 50 times but behind Dan Biggar in the pecking order - injured his hamstring in the European Champions Cup clash between his side Bath and former club Scarlets last weekend.
He was included in the 39-man Six Nations squad this week but further checks led to the decision for him to stay with his club.
"Following further assessments and consultation with a specialist, it has been concluded that due to the severity of Rhys Priestland's hamstring injury, he will remain at Bath Rugby for ongoing rehabilitation and will not link up with the Wales squad on Monday morning," read a statement from the Welsh Rugby Union.
"It is envisaged that the injury will preclude him from taking an active part for the majority of the Six Nations, hence this course of action has been deemed the most appropriate."
Gatland is already without back row forwards Sam Warburton and Dan Lydiate for the whole of the tournament as well as star centre Jonathan Davies.
No 8 Taulupe Faletau is recovering from knee trouble and won't be back until late February or early March.
Wales begin their campaign at home to Scotland on February 3.