Even if you specify a postfix, you shouldn't have issues in deleting characters if the table player%s_deleted exists.
The main reason why you can't delete characters is that "player_deleted" has a different structure than "player", or the table doesn't exist at all. (or your db configs forbid you to do so)
It can be fixed by doing:
create table player_deleted like player;
Thank you for your participation and cooperation with us, but it has been mentioned.