West Ham and Senegal striker Diafra Sakho will miss the 2017 Africa Cup of Nations after being ruled out for up to eight more weeks with a back injury.
The Hammers said on 30 November the 26-year-old would be missing for six weeks because of a thigh injury, meaning he would not return until mid-January.
But boss Slaven Bilic said on Thursday that Sakho faced up to eight more weeks out, taking him to mid-February.
The 2017 Africa Cup of Nations starts on 14 January.
Two years ago, Sakho withdrew from Senegal’s squad with a back injury but scored 18 days later in West Ham’s FA Cup 1-0 win at Bristol City.
As a result, the club were fined £71,000 by world governing body Fifa.
Last month, in only his second appearance of an injury-plagued season, he scored in a 1-1 draw at Manchester United.
The forward, who joined West Ham in 2014 from French club Metz, had only returned from a back injury in the defeat at Tottenham on 19 November.
West Brom were keen to sign Sakho for £15m in August but the deal was called off because of a back problem.
West Ham are 13th in the Premier League table, five points above the relegation zone.
The Hammers visit struggling Swansea on Boxing Day (15:00 GMT) before travelling to Leicester City on 31 December (15:00 GMT).