Watford winger Ismaila Sarr has been ruled out for at least a month with a knee ligament injury.
Sarr, 23, was injured in the 4-1 victory against Manchester United in the Premier League on November 20 and he now appears set to miss the entire festive programme.
The club say he will undergo a further scan on the issue “in around a month’s time”, with his participation for Senegal in the Africa Cup of Nations – being held from January 9 until February 6 – now in doubt.
Ben Foster will also be out injured until January, having missed Sunday’s defeat to Leicester due to a groin strain he had been nursing in recent games.
On Monday, the goalkeeper denied claims he sustained the injury playing in a charity match for Hashtag United.
Ronaldo criticises France Football over Messi Ballon d’Or claims
Rangnick’s permit wait means Carrick will oversee Man Utd vs Arsenal
Transfer Centre LIVE! Will Rangnick eye January recruits?
PL predictions: Palace to send Leeds closer to trouble
Liverpool’s record-breaking attack analysed
Man Utd vs Young Boys could move to neutral venue
F1’s new fastest street track and the big title ramifications
Who will win the Premier League title?
“Unfortunately I injured my groin in training on the Thursday before the Leicester City game, hopefully nothing too major!” he posted on Twitter.
“It certainly had nothing to do with my 15-minute cameo in a charity kickabout earlier in the week! Hope to be back soon.”
Centre-back Nicolas Nkoulou, signed on a free transfer in October, will also be absent until January after picking up a hamstring injury towards the end of the Manchester United match.
Watford host league leaders Chelsea at Vicarage Road on Wednesday, with in-form forward Emmanuel Dennis an injury doubt after sustaining an unspecified injury against Leicester.