First mistake, having someone else inject him. His second mistake was to deny it. He should have said, as part of his therapy, he did take a few injections to help him recover from an injury. Not for an extended period of to enhance his performance, but for a very short time to aid the healing of his injury. Furthermore, based on his experience, he would recommended that any injured athlete consider doing it. This would have left those congressional idiots dumbfounded. I think he is denying it because it will effect his chances for the Hall of Fame and put a black mark on him being considered the best pitcher in baseball's history.
Just my opinion.