West Ham United and Senegal striker Diafra Sakho is facing up to eight weeks on the sidelines with a back injury.
Sakho, 26, has made only two Premier League appearances this season, and will now miss the festive period and next month's African Nations Cup.
Hammers boss Slaven Bilic, speaking ahead of the Boxing Day trip to Swansea, said: "He had a back operation and he's going to be out for up to six to eight weeks. Of course it will rule him out for the African Cup of Nations."
SB: "We have a few knocks but are expecting everyone to be fit except for @iamdiafrasakho who will be out for six to eight weeks.