Pitchers are essentially evaluated in two different areas, in addition to how well they project. Those are what happens before they release the ball and what happens to the ball after they release it. The “Before” obviously has significant impact on what happens to the “After.”
There are also plenty of parallels between what are evaluated as positive pitching mechanics and what are positive hitting mechanics. You’ll see plenty of similar terminology between the two, and many baseball coaches and evaluators look upon the two as mirroring each other in many ways.
I’ll repeat the same thing I said about hitting mechanics: There isn’t one “right” way to throw a baseball. And again, that being said, there are a number of attributes that virtually all successful pitchers share and they tend to be pretty much the same general attributes that good hitters share.
The most important aspect of a pitcher’s delivery, with no exception that I can think of, is that he’s able to repeat his mechanics and thus repeat his release point on all his pitches.
Two things happen to pitchers if they are unable to repeat their pitching mechanics/release point on all their pitches:
1) They will not be able to consistently command their pitches nor have the same quality time after time to their pitches, especially their off-speed pitches. That means they will get hit harder and harder as they move up in competition regardless of the quality of their raw stuff.
2) They will eventually break down and suffer more injuries than pitchers who are able to repeat their mechanics consistently. Do I have empirical evidence of this? No, no one does. But common sense and experience says this has to be the case and I would challenge you to find any experienced baseball person who doesn’t agree.
The two most important things to having repeatable pitching mechanics are your natural athleticism and having a simple, sound delivery.
Since you don’t have much control over your natural athleticism, only your strength and conditioning, it puts the vast majority of emphasis on the second part. And I personally put a huge amount of emphasis on “Simple”.
In basic terms, the more complicated your delivery (i.e., the more check points for various parts of your moving body, whether it be hand, legs, shoulders, etc.), the more variables exist for something to get out of timing or out of rhythm, especially as you get tired. If you have an exaggerated part of your delivery, whether that is a high leg kick or a deep arm stab or a hand wrap in back, those are major variables that can change your balance, rhythm and direction. Likewise, if you do something that is rushed or unnaturally fast, that creates the same potential for doing it differently from pitch to pitch. Anything that can cause your delivery to change from pitch to pitch is essentially evil.
Another thing that creates variables in release point and mechanics is effort. If a pitcher has to put in 100% of his strength in order to create his raw stuff, that’s going to cause problems in the future. Effort creates inconsistency, inconsistency creates lack of command and increased injury potential.
Most evaluators are going to look at a delivery that has lots of variables or effort and downgrade the pitcher because of that. On the flip side, a delivery that stays simple and compact and that a pitcher repeats well means that a pitcher should be able to maximize his physical potential both for stuff and command.
Regarding arm actions and release points, there is also no real right or wrong as long as you can repeat what you are doing in a positive way.
That being said, you won’t find many long arm actions in the Major Leagues. By long arm action, I mean a swinging arm stroke in back that shows the ball behind the pitcher’s body. A longer arm action behind the body that effectively hides the ball from the hitter works well, but the key is not to show the ball to the hitter. I’m convinced that the primary job of many professional pitching coaches is to adjust arm actions to hide the ball from hitters. Some of the changes are subtle, but they are very necessary. Deception becomes increasingly important at the higher levels of baseball and if the hitter can see the ball clearly, he is generally going to hit it solidly.
I personally am not a big fan of straight over-the-top release points. It’s rare to find a loose enough athlete who can throw from a true 12 o’clock release point and not be pulling his head and shoulders (and thus his direction to the plate) severely off. I also consider it an unnatural way for 99% of players to throw. There are exceptions, but they are very rare.
I am probably a bigger fan of lower release points than many evaluators. I think it’s an easier and more repeatable way to throw a baseball as long as you aren’t dropping your elbow too low (big red flag) and it enables you to get more natural movement on your fastball/changeup. It does present problems for many pitchers consistently getting their breaking balls over, so this is an extra-important area to evaluate when you see a lower release point.
There are essentially four different things a pitcher can make a baseball do as it heads to the plate. He can make the baseball a) go fast, b) go slow, c) spin, and d) sink/move. How well a pitcher does those things in combination with his ability to command his pitches is, put most simply, pitching.
A) How hard a pitcher can throw the ball is obviously a huge part of the overall evaluation. You won’t find too many successful college pitchers who don’t throw their fastballs at least in the mid 80’s and most successful professional pitchers will at least work to 90 mph or above on occasion. Velocity just doesn’t apply to fastballs, either. There’s a huge difference for hitters between an 85 mph slider and a 77 mph slider or a 78 mph curveball and a 70 mph curveball.
How hard a pitcher throws on a consistent basis is also very important. A pitcher who throws one fastball 90 mph but over the course of 50 fastballs averages 86 mph does not throw 90 mph, he throws 86 mph. Showcases tend to overemphasize pitchers who throw harder for a limited number of pitches, which is why scouts/college coaches will almost always want to see a young pitcher they are evaluating in true game situations as well.
B) Changeups aren’t just for crafty lefthanders, they are for just about any pitcher who is going to be successful at an upper level. The ability to throw the ball slower with the same arm speed and same release point is extremely valuable. It’s also far less dependent on natural ability than throwing hard or spinning the ball. Learning a changeup is simply a matter of coaching and putting in the effort to learn what grip is most comfortable, then having the confidence to go out and use it in games.
Young pitchers are rarely downgraded in an evaluation if they don’t show a changeup or throw a poor one, but if they do have good feel for the pitch, it can be a big plus.
C) The ability to spin the ball and make it break with some sharpness is obviously something that virtually all successful pitchers have. Whether this pitch is a curveball or slider or some blend of the two (slurve) isn’t as relevant as the ability for a pitcher to spin it consistently from the same release point as his fastball. That last point is very important because if your breaking ball release point is different from your fastball release point, it’s pretty much a worthless pitch against good hitters.
Very few young pitchers throw both a curveball and a slider. In fact, many pitches that are called sliders at the high school level aren’t sliders at all. In the course of a year, Perfect Game scouts will see very few true sliders from high school-age pitchers. 90+% of the time we are evaluating curveballs.
In addition to consistency and release point, curveballs are evaluated on the power of the pitch (a combination of velocity and how hard the ball is spinning), the sharpness of the break, the lateness of the break and the shape of the pitch. A good curveball breaks late and breaks on two planes (i.e. it’s not flat). The same standards apply to sliders as well.
D) The ability to make pitches move/sink applies to fastballs and changeups. At the high school level this isn’t nearly as important as at the higher levels, where it is vitally important. Major League hitters would much rather try to hit a straight 93 mph fastball than an 88 mph fastball that has late life on it.
Movement on pitches comes in all different types but the most important aspects to evaluate are that it’s late, it’s consistent and that it can be used to both sides of the plate.
If a high school pitcher already gets good late life on his pitches, that’s one less thing that he will have to learn as he moves up in the ranks. And teaching movement for even the best pitching coaches is not as simple as just saying “I’m going to teach you to get sink on your fastball today,” like he was tinkering with changeup or slider grips. Some pitchers have difficulty picking up the feel and release while it comes naturally for others.