The fastball (also called hummer and other names) is the most common type of pitch in baseball. Some "power pitchers," like Nolan Ryan, Roger Clemens and Satchel Paige have thrown it at speeds of 95-104 mph (152.9-167.3 km/h) (officially) and up to 107.9 mph (173.6 km/h) (unofficially), relying purely on speed to prevent the ball from being hit. Others throw more slowly but put movement on the ball or throw it on the outside of the plate where the batter cannot easily reach it. The appearance of a faster pitch to the batter can sometimes be achieved by minimizing the batter's vision of the ball before its release. The result is known as an "exploding fastball": a pitch that seems to arrive at the plate quickly despite its low velocity. Fastballs are usually thrown with backspin, so that the Magnus effect creates an upward force on the ball, causing it to fall less rapidly than might be expected. A pitch on which this effect is most marked is often called a "rising fastball", as the ball appears to rise to the batter. Colloquially, use of the fastball is called throwing heat or putting steam on it, among many other variants.
Gripping the ball with the fingers across the wide part of the seam ("four-seam fastball") so that both the index finger and middle finger are touching two seams perpendicularly produces a straight pitch, gripping it across the narrow part ("two-seam fastball") so that both the index finger and middle finger are along a seam produces a sinking fastball, holding a four-seam fastball off-center ("cut fastball") imparts lateral movement to the fastball, and splitting the fingers along the seams ("split-finger fastball") produces a sinking action with a lateral break.
A four-seam fastball is a variant of the fastball.
The four-seam fastball is a pitch that is used often by the pitcher to get ahead in the count or when he needs to throw a strike. The type of fastball is intended to have minimal lateral movement, if any. It is most often the fastest pitch that a pitcher throws, with recorded top speeds in the 100+ mph range. There are two general ways to throw a four-seam fastball.
The first and most traditional way is to find the horseshoe seam area, or the area where the seams are the farthest apart. Keeping those seams parallel to the body, the pitcher places his index and middle fingers perpendicular to them with the pads on the farthest seam from him. The thumb then rests underneath the ball about in the middle of the two fingers. With this grip, the thumb will generally have no seam to rest on.
A two-seam fastball, sometimes called a two-seamer, tailing fastball, or sinker is another variant of the straight fastball.
The two-seam fastball is designed to have more movement than a four-seam fastball so that the batter cannot hit hard, but can be more difficult to master and control. Because of the deviation from the straight trajectory, it is sometimes called a moving fastball.
The pitcher grabs a baseball and finds the area on it where the seams are the closest together. Then, the baseball is rotated so that those seams are perpendicular to his body, with the index and middle fingers on each of those seams respectively. A sinker is a similar pitch thrown with almost the same grip, but with thumb directly underneath the ball. Sinkers are also thrown slightly slower than two-seamers.
Each finger should be touching the seam from the pads or tips to almost the ball of each finger. The thumb should rest underneath the ball in the middle of those two fingers, finding the apex of the horseshoe part of the seam. The thumb needs to rest on that seam from the side to the middle of its pad.
This ball will tend to move for the pitcher a little bit depending on velocity, arm slot angle and pressure points of the fingers. Greg Maddux of the Los Angeles Dodgers, Derek Lowe also of the Dodgers, and Pedro Martínez of the New York Mets are known for their particularly effective two-seam fastballs.
Depending on the grip and pressure applied with the fingers, sometimes the two-seam fastball features more sink than lateral movement. Sinkerballers tend to induce a lot of ground ball outs. This is because hitters tend to swing over the ball due to the late downward movement, and thus, often end up beating the ball into the ground. Jake Westbrook and Fausto Carmona of the Cleveland Indians, Greg Maddux of the San Diego Padres, Brad Penny and Derek Lowe of the Los Angeles Dodgers, Julian Tavarez of the Atlanta Braves, Chien-Ming Wang of the New York Yankees, Jason Marquis of the Chicago Cubs, Aaron Cook of the Colorado Rockies, Brandon Webb of the Arizona Diamondbacks, Jon Garland of the Los Angeles Angels, Roy Halladay of the Toronto Blue Jays, Kyle Kendrick of the Philadelphia Phillies and Bronson Arroyo of the Cincinnati Reds are well known for their sinkers, consistently ranking high in the league in ground ball-to-fly ball ratio.
Such a pitch is known to be physically impossible, due to restrictions of gravity, conservation of momentum, and air density. It has been explained as an optical illusion. What is likely happening is that the pitcher first throws a fastball at one speed, and then, using an identical arm motion, throws another fastball at a higher speed. The higher speed fastball arrives faster and sinks less due to its high speed. The added back-spin from the higher speed further decreases the amount of sink. When the pitch is thrown, the batter expects a fastball at the same speed, yet it arrives more quickly and at a higher level. The batter perceives it as a fastball which has risen and increased in speed. A switch from a two-seam to a four-seam fastball can enhance this effect.
This perception may also created by a tall, hard-throwing pitcher who throws the ball from a higher release point on an elevated mound (the pitcher's rubber is ten inches above the field level). Factoring in the element of depth perception when the hitter watches the pitcher from sixty feet six inches away from the pitcher's mound, and the hitter perceives the pitcher's size and positioning on the mound to be less elevated than it actually is. Hence, to the hitter an overhand pitch will appear to be thrown at a hitter's shoulder level (or even belt level), as opposed to several inches above the hitter's head, from where the pitch is actually released from the pitcher's hand. This perception enhances the apparent "rising" motion of the fastball when the pitch passes the hitter at a higher level than where the hitter perceived the pitch to have left the pitcher's hand.
It is possible for a rising fastball to be thrown by a submarine pitcher because of the technique with which they throw the ball. Because they throw almost underhand with their knuckles near the dirt, the batter perceives the sensation of the ball going upward because of its low starting point and flight trajectory. This is not the traditional rising fastball batters believe they see. Left-hander Sid Fernandez was known for throwing a rising fastball from a slightly "submarine" motion.
It is very difficult to control and stressful on the arm. The reason it is so stressful is that there is tension created in the upper arm as a result of the drastic split of the fingers. This has a tendency to lock the wrist up and prevents there from being any shock absorption at release.
The split-finger is used currently by pitchers such as Chien-Ming Wang, Dan Haren, Kelvim Escobar, José Contreras, Jake Robbins, Jonathan Papelbon, Curt Schilling, Jeremy Accardo, J. J. Putz and John Smoltz. Former players noted for use of the split-finger fastball include Jack Morris, Mike Scott, Kazuhiro Sasaki, Bryan Harvey, Bruce Sutter and Roger Clemens.