Few sports initiate action from the defensive side of the ball. Baseball is one. Nothing happens until the pitcher starts play. Pitching demands a different approach than most sport activities, because more than anything else, it is about deception, not necessarily brute athleticism. Mickey Lolich presented adequate testimony to the difference between athleticism and pitching prowess. If hitting is timing, pitching is about disruption of timing.
Orioles pitching coach Ray Miller preaches three concepts: throw strikes, work fast, and change speeds. Changing speeds disrupts hitters' timing. Major league hitters, even with only 4/10th of a second to evaluate and swing, will catch up with a straight fastball. Witness Matt Mantei's struggles thus far.
A number of extremely successful pitchers, present and past, relied on their ability to change speeds, more than to overpower hitters. For the Sox, Keith Foulke has the 'Bugs Bunny' changeup that seems to stop in midair. Doug Jones, recently, and Stu Miller, in bygone days had similar styles.
Pitchers like Pedro Martinez or Sandy Koufax have multiple 'out pitches', stuff that can be thrown in any count and any situation. Martinez' effectiveness dwindled when he lost enough off his fastball to reduce him from nearly unhittable to merely mortal. His late inning struggles seemed to me to be the result of his ball 'straightening out' with time. The Orioles' Jim Palmer had the ability to work both sides of the plate with both his fastball and slider, taking away the hitter's ability to choose what he would 'give' the pitcher.
Varying arm angles and deliveries presents other alternatives for pitchers. Luis Tiant had the ability to come at hitters overhand, three-quarters, or sidearm, as well as having the peculiar 'back to the hitter' windup. Pitches move differently depending on the arm angle employed. Generally, the over-the-top delivery has less movement than the ball thrown three-quarters or sidearm. Pitchers can also alter their location on the rubber to change the angle to the hitter.
Pitchers can alter ball movement by throwing with the seams (sinking action), across the seams ('rising action' or failure to sink), or alter pressure with their fingers to get the ball to run away from or in on hitters (e.g. the cut fastball). Obviously, specialty pitches (knuckleball, split finger fastball) capitalize on altering ball rotation (less with the fingertip ball-the knuckler thrown with the fingertips) to deceive the hitter.
Catchers and pitchers often study hitters' stances to predict what might be effective. For example, consider a hitter like Carl Everett, with a closed stance, standing close to the plate. These hitters are generally unconcerned about the inside pitch, particularly the fastball, but may be more vulnerable to offspeed pitches and deliveries away. It is said that if Carl Yastrzemski expected a fastball, he would be saying to himself, 'be quick, be quick' and if he was looking offspeed he would say, 'stay back'. Catchers could literally read his lips. If a hitter stands at the front of the box, he is more concerned with offspeed pitches and at the back, looks for a split second longer to deal with hard stuff.
The 'natural corner' for the righthanded pitcher is the inside corner to the righthanded batter. The natural movement of the righthanders pitch is down and in. Generally, pitchers find it more difficult to control the other half of the plate from their natural corner.
Righthanded hitters generally prefer the ball up (waist), while lefthanders are more often lowball hitters. Similarly, because lefties most often see righthanded pitching (down and away), they usually are capable of handling that pitch. You will usually see righthanded pitchers try to get 'under their hands' with hard stuff (fastballs, cutters, sliders) inside and preferably hard stuff up and in (watch how they approach David Ortiz, or remember how they pitched Mo Vaughn). Detailed advanced scouting (the strike zone divided into 9 smaller zones) also allows objective assessment of player strengths and weaknesses.
From a hitter's perspective, there is nothing harder to handle than overpowering fastballs up and in. If a pitcher is blessed with that type of stuff, adding offspeed pitches, particularly breaking stuff down and away, makes hitting a formidable challenge.
I hope you find these generalities interesting while you watch this season and seasons going forward.