Select the "Create Player" option, and choose "Super Player". Give him the same position as the person that you want on your team and maximize the necessary stats to give that player a high rating. For example, making a linebacker and giving it Ray Lewis' tackle stat and the highest pass rush will give him a very high rating. Trade the created player to a team with about the same rating or close to it. If you get the person you want, you can go back to the "Create Player" option and select "Delete Player". You can also delete the other teams' player, thereby taking away a great player from them and making that team weaker while you enjoy your new addition. You can also trade two super players to get a player of higher rating.