Andy Carroll's hamstring injury is so bad West Ham United had to cancel a planned scan on Monday.
The east London club, who worked so hard to sign Carroll on loan from Liverpool, fear that they might be without their powerful centre forward for some time.
A Hammers insider told ESPN: "It looks a bad hamstring, too damaged to scan at the moment."
West Ham might only have Carroll for a limited time after Liverpool manager Brendan Rodgers revealed that they have the option to recall him from his otherwise season-long loan in January.
Carroll was adamant that he didn't want to be forced out of Anfield and even on the morning of the transfer window those closest to him where convinced there was "no chance" of him moving.
Liverpool planned to sign a new striker in the transfer window meaning Carroll's chances would be even more limited and he might not even be on the bench if he stayed at Anfield.
However, Rodgers now regrets letting Carroll go because Liverpool failed to sign either Daniel Sturridge on loan or buy Clint Dempsey from Fulham.
West Ham, though, have ruled out going for Michael Owen or Emile Heskey as a stop gap while Carroll is out injured.