== George Keith == 

 The reference I have lists every player who has signed professional terms with Arsenal and pretty much any player who played for the reserve team upwards. It is possible he was a trialist, however. If you can find a reliable source that affirms both that he was at Arsenal and he was more than a trialist then that can be added in, but Wikipedia consensus is that a player must have signed for a club, not just had a trial, before they can be considered a player at that club.