West Ham United manager Slaven Bilic has revealed his concern after watching Diafra Sakho limp off the pitch against West Bromwich Albion on Sunday.
Sakho had to be substituted in the second half of the 1-1 draw with a left leg injury, and Bilic admits that the forward could be joining Dimitri Payet and Enner Valencia for a spell on the sidelines.
"That worries me more than the result," the Croatian, whose side are currently eighth in the Premier League, told reporters.
"It's still too early before the scan to give a diagnosis but it looks like a muscle injury. It's a big blow for us, he's a key player.
"After losing Valencia and Payet it's a bit too much if I'm honest."
West Ham return to action against Manchester United on Saturday afternoon.
