Tottenham defender Ben Davies has been ruled out of Wales' World Cup qualifier with Serbia on 12 November.
Davies suffered an ankle injury during Spurs' 1-0 defeat by Bayer Leverkusen in the Champions League.
He missed the 1-1 draw at Arsenal on Sunday as the honours were shared in the North London derby.
The 23-year-old had been included in the Wales squad for the qualifier in Cardiff but is now replaced by Adam Matthews.
Davies has started in Wales' opening three qualifiers.
Serbia are top of Group D after three matches with seven points, with Wales in third on five points.