I asked him why he stopped working w/ professional teams and he told me a story about when he was with an NBA team. One of their players got injured and a reporter came up to ask what the injury was. He said "I can't tell you."
The next day the reporter wrote in the paper "Dr ___ doesn't know what's wrong with player X." He went to the reporter and said "Why'd you write that? I know what's wrong. I just couldn't tell you." The reporter shrugged and said "I had a story to write and you wouldn't give me anything."
That wasn't the only reason he stopped, but just another example of not being able to trust the media.