Three... count them 1, 2, 3. Jr high, high school and college, and forget that rubbish about 55 and 60+ fast balls. A) There are just not that many players that fast . B) Any fast ball that dosn't curve, dip, or rise etc is generlly called a double.
So were does that leave us. Well most pitchers say they have 4-5 or even 6 pitches and they all look like fast balls. And it is strange for a pitch has to go 47-48 mph for action to occur i.e drop, curve, etc and 55-57 for a rise ball, that hops ( a fast ball thrown at 50 mph drops 8" from the rubber to the plate due to gravity, so you need the speed to overcome gravity.) so why is it so few pitchers have so few pitches. Poor practice. My DD has kept a journal for over six years of every practice, game etc. and she will tell you that you have to throw 7,500 to 10,000 pitches to start to get the desired action on a pitch 85%+ of the time, and that is not throwing it for strikes, that is just getting a drop to drop. But note once getting the desired action you will quickley find the strike zone.
We are not huge fans of Hillhouse, might have been if I had started with him, but he is correct on three counts.
1) A fast ball that dosn't move is a base hit.
2) The peel drop is better than the turn over drop
because hitters can't pick up on as quick.
3) Use the glove to hide the ball during wind up
to give the hitter less time to pick up the ball
So, a fast ball that moves and a drop that drops. Leaves us developing a change up, and it dosn't have to be one that goes from 55 to 25 mph, but it should be at lest 15 mph differnce with same motion as fast ball and drop.
Finally you need to be able to throw all three to locations and hit the corners and stay around the plate mid thigh and down.