Basically they've ranked each team by position, which includes the starter + back-ups. I found it interesting because it gives you an idea of where certain teams need to improve, such as the Bucks who are pathetic across the board...
Position - Rank
PG - 24
SG - 16
SF - 24
PF - 29
C - 18
Compare this to a successful team, like the Jazz for example:
PG - 4
SG - 18
SF - 8
PF - 3
C - 13
So their weakest position would be the Bucks second best
