The knuckle ball and the split finger fastball (the “splitter”) are two unique pitches that a very small “handful” of professional pitchers use primarily to fool batters during their time on the mound. These pitches are known to be so-called “bread and butter” pitches that certain pitchers use to almost perfection when the pressure is on for them to perform.
Those few “bread and butter” pitchers are almost exclusively known as relievers, as these two special pitches lend themselves better to the relief pitcher’s repertoire instead of those of a starting pitcher. What makes both of these pitches so unique is that by their nature they are difficult to perfect. Many pitchers briefly experiment with one or both of these pitches, but practically everyone quits the effort because of the difficulty factor in learning how to throw it successfully when they need to use it.
The word “knuckle ball” is a misnomer given that the word is supposed to describe a certain type of unique pitch, one that does not spin or rotate. The reason that it is a misnomer is that the knuckles of the pitcher’s throwing hand are not involved in throwing the pitch. Instead, the tips of the fingers are used to grip the ball so that the spin of the ball thrown is reduced to practically no spin at all. That non-spinning pitch is what makes the misnomered knuckle ball do what it does, which is literally whatever it wants to do! For proof of that statement note that any catcher attempting to catch a well-thrown knuckle ball uses the largest glove he can legally (by baseball rules) find in order to catch the pitch. Most catchers of a knuckle ball have somewhat of an idea where the pitch is heading, but their guess is not consistently 100% accurate to say the least.
To correctly throw a knuckle ball, you would grip the ball with the fingertips of the middle and ring fingers while bending in the tip of the index finger at the top knuckle, placing it too on the ball. The fingernails of the middle and ring finger literally dig into the hide of the ball. These three fingers do not grip any seam of the ball. The thumb and pinky form somewhat of a U-shape around the ball, extended somewhat so they are merely guiding the ball. Their fingertips do not touch the ball. As for the launch of the pitch, it is thrown with a stiff-wristed motion, allowing for the ball to be literally casted from the pitching hand. The pitcher’s stride is a bit shorter than his fastball stride so that he can get “on top” of the pitch, the ball thus being launched with the elbow at shoulder height or higher.
The split finger fastball, or splitter, is basically a modern rendition of what was known as the fork ball of yesteryear. The theory behind the splitter is that being thrown with a fastball motion and delivery, it appears to the batter as the pitch is a fastball coming at him, he only to have the pitch drop very quickly and suddenly as it gets very near or over home plate. The hand and finger setup and execution for the splitter has the pitcher literally jamming the ball back into his hand as he spreads his index and middle fingers. The index and middle finger are then in a position to put enough pressure on the ball at release of what would otherwise have been a fastball. The ball has its spin impeded enough so that it begins to slow down in velocity as it nears the plate. Simply put, the splitter falsely appears to be a fastball. The pitcher is “choking off” the spin by applying added pressure to the ball. He is using the two fingers, the index and middle finger to do so, literally jamming the ball between them. When gravity overcomes velocity, as regards to pitching a baseball, the ball falls to the ground. In essence, that is what the splitter does. The splitter is thrown with the same motion as the fastball, thus disguising that it is indeed a splitter whose “bottom is about to fall out of it!” A well-thrown splitter will fool almost any batter, even the best. However, once the splitter is known to the batter, the smart batters move up in the batter’s box in order to hit the splitter Before it begins its decent. This is the major problem a pitcher who relies on a specialized pitch has to face. Relief pitchers use specialized pitches such as these two almost always for one inning, while starting pitchers use it sparingly.
Both the knuckle ball and the splitter are excellent pitches to employ if you can learn the art of throwing either of them successfully, especially doing so while under pressure. The knuckle ball is by far the more unique and difficult to learn of the two pitches. It tends to be a pitch where you either can do it or you cannot, so the process can begin and end quite quickly. The splitter can be thrown by most pitchers over time with plenty of practice. However, it is a dangerous pitch for any professional to use as it can cause severe elbow injury due to overuse or one ill-timed poor throw. Tendons and elbow area ligaments will be strained by throwing the splitter too much. In contrast, the knuckle ball can be thrown with very little arm pressure or fatigue.
Both of these unique pitches are worth trying to develop, but it would behoove the pitcher to not take too long in their learning curve process. Instead, a good sinker and slider make far more sense to develop than the knuckle ball or splitter. For proof of the veracity of that statement, note that today there are practically no professional pitchers who throw the knuckle ball and very few who throw the splitter. However, sinker ball pitchers and slider specialists are to be found on almost every major league team. For aspiring amateurs, concentrating on the art of throwing the sinker and slider make far more sense than attempting to perfect either the knuckle ball or the splitter.