Wales fly-half Sam Costelow has been ruled out of the Six Nations trip to face Ireland on Friday night.
Costelow, 25, suffered an ankle injury in the second half of the 26-23 defeat by Scotland nine days ago but was retained in the Wales squad last week.
The Scarlets number 10 is not to fit to travel to Dublin but could still be involved in the tournament finale against Italy on 14 March in Cardiff.
Costelow is set to be replaced by either Jarrod Evans or Dan Edwards, who was dropped against Scotland after starting the previous seven matches.
Wales head coach Steve Tandy will officially name his team on Wednesday and will also have to replace injured Scarlets flanker Taine Plumtree, who has been ruled out of the tournament.