Fly-half Rhys Patchell is a World Cup worry for Wales after suffering a head injury during their final warm-up against Ireland in Dublin.
The pivot left the match after only 23 minutes to be replaced by Dan Biggar.
Wales are already without Six Nations Grand Slam number 10 Gareth Anscombe, who suffered a knee injury in defeat to England on 11 August.
Patchell suffered two concussions during 2018-19 playing for Scarlets and is due to fly to Japan on Wednesday.
Patchell who beat Cardiff Blues’ Jarrod Evans to a place in Wales’ 31-man squad, departed for a head injury assessment and did not return to the match at the Aviva Stadium.
Former Wales wing Adrian Hadley told BBC Radio Wales: “With his history, that head knock is a worry for Rhys Patchell. He took a knee to the head.”