When you start a franchise, make sure that edit rookie is turned on. Then after your first season, when draft time comes go to ESPN.com and then go to rookie report. Then go to the postiion you want to play as, and scroll down untill you see the picture you want to be your player, then just edit him.

Also a little hint wich you could call cheating is make him the worst or close to the worst at his position and wait till your 7th draft pick. Exit the draft screen and go to ESPN.com then go back to the rookie you want for your created person, and make his stats to where you want them. Then when you draft him at #7 you will have a great player and you will only have to pay him about 80 thousand dollers a year.