I believe the doctor who did the medical commented that Carroll was not a healthy specimen and hadn't looked after himself. We were fully aware that his jumping style meant he always landed on the same foot, meaning there was an enhanced risk of injury to the joints in that leg. The people responsible for the due diligence did their jobs properly (and they didn't need to do a lot to find red flags), but their warnings were ignored.And alcoholism. The amount of background work the club did on Andy Carroll could have been written on a post card.