West Ham United manager Slaven Bilic has revealed that Victor Moses could be facing a six-week spell on the sidelines.
Moses was forced off in the first half of Saturday's goalless draw with Manchester United after picking up a hamstring injury while challenging for the ball.
It adds to the injury concerns for Bilic, who is already without attacking quartet Dimitri Payet, Enner Valencia, Manuel Lanzini and Diafra Sakho.
"We have to wait for a scan but it doesn't look good," the Hammers boss told reporters.
"It's almost impossible to replace them. But we replaced them today and this point was well deserved. As it was done without those players, it makes it even bigger."
West Ham have not won any of their last five games.