Jack Sullivan, son of West Ham United chairman David Sullivan, has confirmed that defender Winston Reid has picked up a hamstring injury.
The 27-year-old reportedly picked up a knock in training, and Sullivan has suggested that Reid will be out of action for four to six weeks.
Reid - who signed a new six-year contract at Upton Park earlier this year - was absent for a month earlier this season, and Sullivan told Hammers fans on Twitter that the New Zealand international will be unavailable for the Christmas period.
Reid could miss West Ham's fixture against Stoke City on Saturday afternoon.
