West Ham and Senegal striker Diafra Sakho will be out for six weeks with a thigh injury, his club have confirmed.
The 26-year-old scored in the 1-1 draw at Manchester United in only his second appearance of an injury-plagued season.
Sakho, who returned from a back injury in the defeat at Tottenham on 19 November, was substituted in the 66th minute at Old Trafford.
"It's a big blow for us," Hammers boss Slaven Bilic said before Sakho's scan results were revealed on Wednesday.
Senegal are hoping Sakho will be fit and available for the Africa Cup of Nations, which starts in January.