Go to "Player Management", then to "View Roster". Select the player you want to power up or down. Press R or L until you see his "Pitching" or "Batting" attributes. The red area in all of the bars represents how skilled that player is in the category shown next to it. Press Left or Right to increase or decrease the skill. -From: gAmEbOy2
Release a player as a free agent. You can now rename him, then resign him.