Potential in Draft Editor

[klausdark6]

Hello friends!
New to the game and the community.
I love to edit and create stuff in games like this one.
So i started to create a draft class, and after some research on game and in the internet, i cant find what attribute or something like this dictate the 'potential' of a player.
An example:
I like to set some player with low ratings' but a lot of future, and some players already developed almost at his limit.
Any tips?
Thx!