Ben Davies has withdrawn from the Wales squad to play Serbia in Saturday's World Cup Qualifier after picking up an ankle injury.
The left-back, who also plays on the left side of a back three for his country, suffered the knock during Spurs' 1-0 Champions League defeat to Bayer Leverkusen and missed the 1-1 draw with rivals Arsenal on Sunday.
He has been replaced in the squad by Bristol City's Adam Matthews, who is on a season-long loan from Sunderland.
His absence is a huge blow for Chris Coleman after a stuttering start to Wales' World Cup qualifying campaign.
The 23-year-old has started in Wales' three World Cup Group D qualifiers, which have seen them beat Moldova 4-0 before drawing 2-2 in Austria and 1-1 at home to Georgia.
The two dropped points against Georgia mean the clash with Serbia, live on Sky Sports, has taken on extra significance.
Coleman's side sit third in the group, two points behind Serbia, who are top on goal difference ahead of the Republic of Ireland.
Davies said after the Georgia draw: "It's definitely a big game now," said Davies. "It's one we really have to get something out of.
"It's a game we really need to get ourselves together for. We have to look back at what went wrong and rectify it."