Strike zone
Encyclopedia
In baseball
Baseball
Baseball is a bat-and-ball sport played between two teams of nine players each. The aim is to score runs by hitting a thrown ball with a bat and touching a series of four bases arranged at the corners of a ninety-foot diamond...

, the strike zone is a conceptual right pentagon
Pentagon
In geometry, a pentagon is any five-sided polygon. A pentagon may be simple or self-intersecting. The sum of the internal angles in a simple pentagon is 540°. A pentagram is an example of a self-intersecting pentagon.- Regular pentagons :In a regular pentagon, all sides are equal in length and...

al prism over home plate
Home Plate
Home Plate is the fifth album by Bonnie Raitt, released in 1975 .-Track listing:#"What Do You Want the Boy to Do?" – 3:19#"Good Enough" – 2:56#"Run Like a Thief" – 3:02...

 which defines the boundaries through which a pitch
Pitch (baseball)
In baseball, a pitch is the act of throwing a baseball toward home plate to start a play. The term comes from the Knickerbocker Rules. Originally, the ball had to be literally "pitched" underhand, as with pitching horseshoes. Overhand throwing was not allowed until 1884.The biomechanics of...

 must pass in order to count as a strike when the batter
Batting (baseball)
In baseball, batting is the act of facing the opposing pitcher and trying to produce offense for one's team. A batter or hitter is a person whose turn it is to face the pitcher...

 does not swing.

Definition

The top of the strike zone is a horizontal line at the midpoint between the top of the batter's shoulder
Shoulder
The human shoulder is made up of three bones: the clavicle , the scapula , and the humerus as well as associated muscles, ligaments and tendons. The articulations between the bones of the shoulder make up the shoulder joints. The major joint of the shoulder is the glenohumeral joint, which...

s and the top of the uniform pants. The bottom of the strike zone is a line at the hollow beneath the kneecap. The right and left boundaries of the strike zone correspond to the edges of home plate. A pitch that touches the outer boundary of the zone is as much a strike as a pitch that is thrown right down the center. A pitch at which the batter does not swing and which does not pass through the strike zone is called a ball.

The de facto
De facto
De facto is a Latin expression that means "concerning fact." In law, it often means "in practice but not necessarily ordained by law" or "in practice or actuality, but not officially established." It is commonly used in contrast to de jure when referring to matters of law, governance, or...

enforced strike zone can vary. An extreme interpretation that favors batters requires the entire diameter of the ball—including stitched seams— to pass inside the area formed by the strike zone boundaries as defined in the official rules. The opposite extreme—favoring pitchers—requires a pitch to be called a strike if even the smallest portion of the ball, seams included, has intersected or passed inside any strike zone boundary as defined in the official rules.

A batter who accumulates three strikes in a single batting appearance has struck out
Strikeout
In baseball or softball, a strikeout or strike-out occurs when a batter receives three strikes during his time at bat. A strikeout is a statistic recorded for both pitchers and batters....

 and is ruled out
Out (baseball)
In baseball, an out occurs when the defensive, or fielding, team effects any of a number of different events, and the umpire rules a batter or baserunner out. When a player is called out, he is said to be retired...

 (with the exception of an uncaught third strike); a batter who accumulates four balls in a single appearance has drawn a base on balls
Base on balls
A base on balls is credited to a batter and against a pitcher in baseball statistics when a batter receives four pitches that the umpire calls balls. It is better known as a walk. The base on balls is defined in Section 2.00 of baseball's Official Rules, and further detail is given in 6.08...

 (or walk) and is awarded advancement to first base. In very early iterations of the rules during the 19th century, it took up to 9 balls for a batter to earn a walk; however, to make up for this, the batter could request the ball to be pitched high, low, or medium.

Enforcement

While baseball rules provide a precise definition for the strike zone, in practice it is up to the judgment of the umpire
Umpire (baseball)
In baseball, the umpire is the person charged with officiating the game, including beginning and ending the game, enforcing the rules of the game and the grounds, making judgment calls on plays, and handling the disciplinary actions. The term is often shortened to the colloquial form ump...

 to decide whether the pitch passed through the zone. Historically, umpires often call pitches according to a contemporary understanding of the strike zone rather than the official rulebook definition.

Many factors have contributed to the divergence of the official and conventional strike zones in Major League Baseball
Major League Baseball
Major League Baseball is the highest level of professional baseball in the United States and Canada, consisting of teams that play in the National League and the American League...

. Changes began in the 1970s, when umpires upgraded their chest protection in favor of more compact vests allowing them more movement. Crouching lower meant lowering their line of vision, and caused the boundaries of the strike zone to sink lower. Thus, the strike zone was often enforced such that pitches above the waist were balls, and pitches a few inches outside of home plate were called strikes. As pitchers lost the higher strike zone, they began throwing lower and to the outside, which caused hitters to move much closer to the plate.

At the same time, there was a shift in attitude among both players and league officials regarding pitches thrown inside. While pitchers of the 1960s such as Bob Gibson
Bob Gibson
Robert "Bob" Gibson is a retired American professional baseball player. Nicknamed "Hoot" and "Gibby", he was a right-handed pitcher who played his entire 17-year Major League Baseball career with St. Louis Cardinals...

 regarded it a pitcher's right to throw high and inside, later batters were more likely to take offense at such treatment. Major League Baseball also tightened its rules prohibiting pitchers from intentionally hitting batters, removing the warning pitchers formerly received before being ejected from a game. Soon, hitters moved closer to the plate and looked for the ball outside.

In 2001, Major League Baseball directed its umpires to call pitches according to the official definition rather than the conventional one. Umpires were to call "high" strikes and "inside" strikes, while pitches just off the outside part of the plate were to be called balls. The umpires demonstrated limited compliance for a time, but before long the de facto strike zone had returned to the conventional definition. Shortly thereafter, Major League Baseball began privately evaluating umpires based on the QuesTec
QuesTec
QuesTec is a digital media company that pioneered virtual replay from real-time measurement data for baseball and tennis. Years before competitors introduced similar products, QuesTec had established a reputation for accuracy and reliability...

 pitch-tracking system. Most umpires, players and analysts, including the authors of a University of Nebraska study on the subject, believe that due to QuesTec, the enforced strike zone in 2002-2006 was larger compared to the zone in 1996-2000 and thus closer to the rulebook definition. Some commentators, such as Tim Roberts of covers.com, believe that the zone has changed so much that some pitchers, such as Tom Glavine
Tom Glavine
Thomas Michael Glavine is a former Major League Baseball left-handed pitcher.With 164 victories during the 1990s, Glavine was the second winningest pitcher in the National League, second only to teammate Greg Maddux's 176...

, have had to radically adjust their approach to pitching for strikes.

In 2009, a new system called Zone Evaluation was implemented in all 30 Major League ballparks, replacing the QuesTec system; the new system records the ball’s position in flight more than 20 times before it reaches home plate. Much of the early resistance from Major League umpires to QuesTec had diminished and the implementation of the new Zone Evaluation system in all the parks went largely unnoticed. Like the old system, the new system will be used to grade umpires on accuracy and used to determine which umpires receive post season assignments.

Worldwide

The Nippon Professional Baseball rules had defined the strike zone slightly differently until 2009.

External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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