West Ham manager Slaven Bilic says he expects striker Diafra Sakho to be sidelined for up to two months with a thigh injury.
The Senegal international picked up the knock in Sunday's 1-1 draw against West Brom at Upton Park and, even though the Hammers are still awaiting the results of a scan, Bilic is fearing the worst.
The Croatian said: "It's not good. It will be four to eight weeks. Maybe more. He has a bit of history with his thigh. It's a muscle injury. Nothing long term, but we will be without him for a few games, definitely."
Sakho is the latest attacking player to be struck down by injury as the east London club have already lost Dimitri Payet and Enner Valencia, both due to ankle problems.
Andy Carroll, who has returned to the team recently after six months on the sidelines, is expected to lead the line against Manchester United on Saturday.