So most of the time we hear about pitchers velocity (90-96 mph) or types of pitches (fastball, slider, curve, cutter, forkball, knuckleball or change).
Now field managers and coaches want their pitchers to work the batter, and set up their out pitch.
But the emphasis is on throwing the ball at speed and location rather than understanding the art of pitching. As Greg Maddux used to point out he was not a thrower, but a pitcher. His greatest weapon was the ability to change speeds of his fastball to throw off the batter.
The batter has less than a second to digest a lot of information. First, where is the pitcher's release point. Second, what is the rotation on the ball. Third, what is the velocity of the ball. Fourth, is it in my hitting zone. The harder it is to pick up the first flight of the pitch, the harder it is to adjust and hit it. A batter relies upon eyesight, intuition and quick reflexes in order to hit major league pitching.
A pitcher should realize that he has the initial advantage. He knows what pitch he is about to throw the hitter.
Now coaching has given pitchers the concept of consistency as being the key to success. Coaches prefer to coach players who are like batting cage machines. They have the same delivery, arm motion and arm slot. For coaches, this is important in a job preservation sense. When a pitcher loses command over his pitches, the coach can compare film on the player to determine what changes, if any, is in his delivery. Pitching coaches are more concerned about throwing the ball than the art of pitching to a batter.
A starter may have three pitches: fastball, slider and curve. He may throw his fastball 55% of the time, his slider 35% of the time, and his curve 10% of the time. Scouting reports will break down the data, frequency, pitch counts and out pitches. But this does not take into consideration the variables to standard pitching: change of speeds and change of release angles.
Change of speeds as Maddux stated is probably more important than location. If one has a 94 mph fastball, if you can change its speed to 88 mph with the same motion, the batter will be fooled into swinging early. In essence, the pitcher has created a "second pitch" with the same grip and delivery.
The least used variable is change to pitching angles.
If you divide a pitcher in clock sections, you can see the zones where a pitcher's arm will pass through on the way toward the plate. Some famous curve balls were called "noon to six" pitches because they looked like they released over the head of the pitcher and dropped steeply when crossing the plate. It is rare for a pitcher to have a pure overhead delivery. Most pitchers today use a 3/4 delivery where they can power their shoulder down the line toward the plate for the most leverage. A sidearm delivery can be effective with the full body torque. Rick Reuschel had this easy motion which complimented his slider into ground ball outs. The submarine pitcher is one who is looking to surprise a batter with an odd pitching angle. Usually, these submariners have a quirky body rotation to further conceal the ball as long as possible since these style pitchers normally have a lower ball velocity. On some occasions, a veteran pitcher like Jake Peavy, will submarine a pitch to a batter late in the count in a tight situation to increase his chances for a strike out.
Pitchers do no use all their arm angles during a game. They are taught to find one arm slot and use it over and over again to get repetition control. But in theory, a two pitch 3/4 pitcher (fastball and slider) can create "four" more pitches just by going sidearm or submarine. Again, if a pitcher is looking for an edge against a batter, the change or disguise of his pitching release point angle is the first thing a pitcher can do to confuse a batter.
