Cheats > Game > Cheat: 26322

Easy win
Start a game with and set the skill level on anything except "Manage Only". Pause gameplay go to "Controller Select". Switch the controller to the team that you want to lose. Then, go into "Team Management" at the pause screen. Change the pitcher and the fielders to the wrong positions. You can also put pitchers in as pinch hitters. Then, return to "Controller Select" and change back to your original team. The CPU may switch the players around, but you can put the wrong ones in again. You will not get any card points if you play the entire game with the losing team. Note: There is a slight chance of your game freezing if player positions are swapped too often.