West Ham defender Ryan Fredericks has been ruled out until February with a hamstring injury having hobbled off at Gillingham on Sunday night.
The 27-year-old was forced off in the first half at Priestfield and needed help to make his way off the pitch during West Ham's 2-0 FA Cup win.
Pablo Zabaleta replaced the former Fulham man and bagged his first goal for the club on his 75th appearance and could now be set for a longer spell in the side after a scan revealed the damage done to Fredericks.
West Ham's head of medical, Richard Collinge said: “Ryan injured his hamstring while chasing back late in the first half and was assessed immediately before undergoing a scan.
“He will now begin a period of rehabilitation and recovery, with the plan being to return to action before the end of February.”
Hammers boss David Moyes - who has two wins from two since his return to the club - may have to re-think his tactical switch to a back three, which was so well used during his first spell at the club, following the loss of Fredericks.
The Scotsman faces a tough first month in the job with six games across January, including a rearranged game against Liverpool which was due to be played in December while the Reds were at the Club World Cup.
