[SilentTom]

I had the same question and it was answered for me in another thread...when you pause the game you will see the two teams logos on the right and below it (similarily across from the Save/Quit option more or less) there is something that says "USER" with L1 and R1 on either side (at least that is what it is for PS2) and clicking either will change it to CPU, where you only control your player.