Tottenham defender Ben Davies is expected to be sidelined for an "extended period" after suffering ankle ligament damage.
Davies, 26, was injured during Saturday's 3-2 win at West Ham and was substituted after 75 minutes of manager Jose Mourinho's first game in charge.
A statement on the club website read: "Following ongoing examination and assessment over the past few days, we can confirm that Ben Davies sustained ligament damage to his left ankle during Saturday's win against West Ham United.
"Assessment continues to determine whether surgery is required, with the Wales international defender expected to undergo an extended period of rehabilitation."
After watching his side come from behind to beat Olympiacos in the Champions League on Tuesday, Davies walked through the mixed zone on crutches wearing a protective boot.
He told the PA news agency: "It doesn't look good. It will be a while."
Davies has made nine appearances in all competitions for Spurs this season and also helped Wales secure qualification for Euro 2020 earlier this month.
