West Ham striker Diafra Sakho has undergone a scan and will see a specialist to learn the extent of his thigh injury.
Sakho suffered what the club have described as "a significant injury to his left thigh" during the second half of Sunday's 1-1 Premier League draw with West Brom.
The Senegal international has scored five goals in 14 appearances this season but the last of those came at the end of September before he was sidelined for a month by a thigh problem.
"Diafra unfortunately suffered a significant injury to his left thigh during Sunday's Premier League draw with West Bromwich Albion," said West Ham's head of medical and sports science Stijn Vandenbroucke on the club's official website.
"He underwent a scan on Wednesday and will see a specialist on Thursday, when we hope to learn more and put a more certain timeframe on his absence."
Vandenbroucke added more positive news on the recovery of Sakho's fellow forward Enner Valencia from an ankle injury.
Valencia completed the latest stage of his rehabilitation in his native Ecuador and he is expected to be back in action before the end of 2015.
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