West Ham have confirmed Kurt Zouma has suffered a serious hamstring injury, in a second significant defensive blow.
Centre-back Zouma is facing months out after scans confirmed the severity of the injury that forced him off in Saturday's 3-2 win against Chelsea.
West Ham were awaiting the results of a second check on Zouma's injury before discovering the full extent of the setback.
There were initial concerns that Zouma had suffered a problem in his knee.
A statement released on Tuesday said: 'West Ham United can confirm that Kurt Zouma sustained a hamstring tendon injury during Saturday's Premier League victory against Chelsea.