Ok here are my ideas, some are the same as in your diagram McQwak.
Click here
(I expect to have more tables but this is the big picture right now)
I am gonna add a few words to describe it.
Persons and
Competitions will not be tables, I just drew them to get less lines in the diagram. All lines going from/to
Persons will be part of
Staff and
Players and the same thing for
Competitions, in this case
Tournaments and
Leagues.
I have some boxes with a Stats suffix, these will be separate tables storing stats for
Players,
Staff and
Teams.
The two relationship boxes will store relationships between
Persons and
Teams. As every person/team doesn't have the same number of good/bad relationships I chose to store them all in their own tables (same reason for the different stats). So for example relationships between all teams will be stored in the same table.
Tournaments will store tournaments like the Olympics etc, these events are usually associated with a specific arena or two; that is not the case for a league (every team has its own arena).
As for the
Draft History, I drew it so that a player knows when he was drafted, a team knows who it drafted and when as well as the league who knows who every team in the league drafted and when.
I hope you understand the diagram, it got kind of messy in the end. If there are inconsistencies in the diagram/text please let me know as well as if something obvious is missing. Any questions and suggestions are welcome.