Sam Allardyce has admitted that it will be difficult for his West Ham United side to "break down" Hull City in the Premier League this weekend.
The Hammers, who currently sit seventh in the table, have kept just four clean sheets in the league this season.
The manager told reporters: "The fact we haven't won in the league for a few games is a cause for concern.
"We've been free-scoring this year but we've only got four clean sheets and because of that it has cost us 1-0 wins that you look for when the games are tight. They will be difficult to break down and difficult to beat when they come here."
West Ham have not won in their last four matches.
