West Ham United defender James Collins faces a spell on the sidelines after picking up a hamstring injury during the 2-1 defeat at Bolton Wanderers.
Hammers boss Gianfranco Zola fears the worst, after watching Collins being stretchered off the pitch moments after Bolton's second goal.
"He is going to have a problem," said the Italian. "It's a hamstring.
"How long it's going to be I don't know but it isn't looking very good. We don't know.
"He's going to have a scan. It's a pity because James has been playing very well and we're going to have to lose him for a while."
Of his side's display at the Reebok Stadium, Zola added: "The only complaint I have is we didn't take the chances we created.
"It's a pity because the performance was the performance of a team that didn't deserve it.
"This is football. You cannot afford to concede anything to Premier League teams because they take advantage, so it is a good lesson for us for the future."