Glossary of pitch types

From Off Speed: Baseball, Pitching, and the Art of Deception by Terry McDermott

• Four-seam fastball- a straight fastball, almost always the fastest pitch any pitcher can throw. It is called a four-seam fastball because it is gripped across the seams. This is the most common pitch. Speeds can range from low-80s mph to more than 100 mph.
• Two-seam fastball- a fastball gripped with the seams rather than across them. The two-seamer sinks and often moves from left to right from a right-handed pitcher.
• Curveball- the most basic breaking pitch, it is gripped with the middle finger along a seam and thrown with a strong snap of the wrist to the right for a right-handed pitcher; this imparts spin to the ball, causing it to break both horizontally right-to-left and down.
• Slider- a faster breaking ball than the curve, but slower than a fastball. It breaks more horizontally and less vertically than a normal curve. It is not as fast as a fastball but is faster than the rest of a pitcher’s pitches. It is gripped like a two-seam fastball but slightly off center, so that the ball is released off the thumb side of the index finger.
• Cut fastball- the cutter lies halfway along a continuum between a fastball and a slider. The grip is almost identical to a four-seam fastball, but the fingers are moved slightly to the right and more pressure is put on the ball with the middle finger. There is no wrist snap. To the hitter, the pitch looks identical to a fastball. It breaks very little, but does so very late.
• Changeup- a change-of-pace pitch that is thrown as if it is going to be a fastball but that leaves the hand as much as 10 mph slower. The most common change grip in use today is the circle change, in which the index finger and the thumb are used to form a circle to the side of the ball which is held in the other three fingers. The hand is turned so that the circle is facing the ground as the pitch is released. The combination of the grip and the downward turn of the hand lessens the speed of the pitch and often imparts a slight right-to-left break from a right-handed pitcher.
• Sinker- similar to and sometimes synonymous with the two-seam fastball.
• Splitter, or split-fingered fastball- similar to a sinker but with a much sharper downward break. The ball is gripped with the index and middle fingers spread as far as feasible on the outside of the seams. The pitch is thrown with the same motion as a fastball but is typically somewhat slower, and it dives as it reaches the plate.
• Forkball- similar to the split-fingered fastball but gripped more deeply in the hand and with somewhat less spread between the top fingers; it is slower and has less spin than the split.
• Knuckleball- an unpredictable, erratic, impossible-to-hit pitch that has little to no spin; it is the only sort of pitch that might break twice in opposite directions. It is gripped not with the knuckles but with the fingertips of the middle and index fingers, placed directly behind the seam. The thumb and ring fingers are placed on opposite sides, also outside the seam. The goal of the pitch is to have as little spin as possible, causing the ball to move unpredictably even when a hitter knows with 100 percent certainty that the knuckler is coming.
• Eephus- a lob; it has the trajectory of a slow pitch softball pitch. Only one or two pitchers per generation ever throw it in a game.
• Screwball- a backward curveball. That is, it breaks down, but in the opposite direction of a curveball. It is gripped like a curve, but the wrist is turned in the opposite direction, toward the pitcher’s glove side, upon release.
• Spitter- an illegal pitch to which a foreign substance—saliva, Vaseline, hair cream, or who knows what—has been applied, causing the pitch to drop suddenly as it approaches home plate. It is thrown with the same grip and motion as a fastball. Its trajectory is similar to that of a split-fingered fastball. There is widespread suspicion that many of the great split-finger practitioners were, in fact, throwing spitters, not splits.

Sources:

• Off Speed: Baseball, Pitching, and the Art of Deception by Terry McDermott