London, England (SportsNetwork.com) - West Ham defender James Tomkins could miss the rest of the season after suffering a dislocated shoulder in training on Thursday.

The club has confirmed that Tomkins received treatment at the hospital for the injury, although West Ham has yet to put a timetable on his return.

West Ham manager Sam Allardyce is already without center back Winston Reid for Saturday's trip to Arsenal, so the injury to Tomkins comes as a further blow to the 10th-placed side.

The 25-year-old Tomkins has been a regular in Allardyce's team, starting 20 Premier League games and scoring one goal with three assists.