Crystal Palace midfielder Jonny Williams will miss Wales’ opening World Cup qualifier against Moldova on 5 September because of an ankle injury.
Williams suffered the injury in a pre-season game against Farnborough.
The 22-year-old could also miss the games against Austria and Georgia in October and is expected to be out for up to 10 weeks.
He was part of the Wales squad for Euro 2016, starting the opening game against Slovakia.
“It’s another injury for Jonny and we hope it’s not too long,” Wales assistant manager Osian Roberts told BBC Radio Wales Sport.
“It’s really disappointing for Jonny because we thought this would be the season he would make that major step in his career.
“It’s really disappointing it’s come in a friendly and I’ve seen the tackle, it’s a poor one and one we don’t want to see in the game anymore.
“It’s one from behind with both legs wrapped around the ankle and subsequently it’s another injury for Jonny.”