I like to take a pitcher with a good curveball and sneak one up in the zone a couple times a game. If I miss high, it's all good still. I don't know if it matters against the CPU though, not like you can truly surprise them like you could a human opponent.
Tried to hook one in on the high inside corner against Ryan Braun in a game yesterday. I was hoping to freeze him. The pitch ended up dead center, and the hit ended up in the left field bleachers.
I do not throw change-ups or splitters up in the zone intentionally unless it is also off the plate.