The 32-year-old defender was carried away on a stretcher after receiving oxygen on the pitch, having fallen heavily following a collision with Hammers team mate Roger Johnson on Saturday.
He suffered concussion and a damaged shoulder and was unconscious for several minutes before spending the night in hospital in Cardiff.
British media reported he had suffered neck and shoulder injuries, adding to West Ham's already considerable injury list.
The victory took West Ham out of the relegation zone into 17th position, one place above Cardiff.
- Sports & Recreation