West Ham striker Andy Carroll has an ankle injury and faces a possible lengthy absence, Press Association Sport understands.
Carroll has been linked with a move to Premier League champions, but now any move in January appears to be unlikely after a scan revealed the severity of the injury on Thursday.
Surgery is among the options being considered and, if 29-year-old Carroll underwent an operation he would be out for months, rather than weeks.
Hammers boss David Moyes is likely to address the matter in his media conference on Friday ahead of Saturday's Premier League clash at home to Bournemouth.
Carroll has not played since January 4 against Tottenham.
Moyes was at Chelsea's FA Cup replay with Norwich on Wednesday night, apparently watching Belgium striker Michy Batshuayi.
Batshuayi scored Chelsea's first goal in more than five hours, but his overall performance was underwhelming as he frequently squandered possession.