You get the points assigned for the position you draft the player in.
If you use the player as assistant manager, you get points for assistant manager.
If you use the player in the field or as reserve player you get the points for the player based on what he has done during the game.
Good to know that i'm on the right track from the start.

After the players retired though, the interest to buy their cards isn't quite big and a lot of users have cards with those retired players but their points will be flat.
Do you plan to do something about those cards? Maybe some trade with the new upcoming card players or a swap?
We didn't think to that but we will look into it.
On the other hand before retiring they would have scored points for you and you would have gotten your money back from prizes and you can still use them as assistant managers.