I would assume that St Kilda would have a comprehensive medical file on every player. I would assume that the appropriate file, with player permission, would be forwarded to the new prospective employer. The medical examination would be to clarify issues that are contained in the medical file and to confirm that the player assessment and the medical history/file are consistent.
I would hope that the process is per-functionary and based on a underlying need for "due diligence" rather than any real expectation of the Docker's medical staff actually doing anything that requires much skill.