I'm not a health care professional...and, frankly, I haven't read all the posts in this thread: I'm too tired and its too late.
However, I will add, that as an attorney, I advise all my umpire friends:
If they themselves have first-hand knowledge that a player became "apparently unconscious" OR they are told from a reliable source (i.e. a trainer, coach, etc.) that the player was unconscious...there is no friggin' way that player is coming back in the game unless I receive a note (in triplicate
) signed by a MEDICAL DOCTOR (MD). Period, end of discussion.