Editing Baseball rules (section)

=====Pitching=====
[[File:baseball pitching motion 2004.jpg|thumb|left|The typical motion of a right-handed pitcher]]
{{main|Pitcher}}

Effective pitching is critical to a baseball team, as pitching is the key for the defensive team to retire batters and to prevent runners from getting on base. A full game usually involves over one hundred pitches thrown by each team. However, most pitchers begin to tire before they reach this point. In previous eras, pitchers would often throw up to four complete games (all nine innings) in a week. With new advances in medical research and thus a better understanding of how the human body functions and tires out, starting pitchers tend more often to throw fractions of a game (typically six or seven innings, depending on their performance) about every five days (though a few complete games do still occur each year).

A single game often requires multiple pitchers, including the [[starting pitcher]] and [[relief pitcher]](s). Pitchers are substituted for one another like any other player (see above), and the rules do not limit the number of pitchers that can be used in a game; the only limiting factor is the size of the squad, naturally. In general, starting pitchers are not used in relief situations except sometimes during the post-season when every game is vital. If a game runs into many extra innings, a team may well empty its [[bullpen]]. If it then becomes necessary to use a "position player" as a pitcher, major league teams generally have certain players designated as emergency relief pitchers, to avoid the embarrassment of using a less skillful player. In baseball's early years, squads were smaller, and relief pitchers were relatively uncommon, with the starter normally remaining for the entire game unless he was either thoroughly ineffective or became injured. Today, with a much greater emphasis on pitch count, over the course of a single game each team will frequently use from two to five pitchers. In the [[2005 American League Championship Series|2005]] [[American League Championship Series|ALCS]], all four of the [[Chicago White Sox]] victories were complete games by the starters, a highly noteworthy event in the modern game.

While delivering the ball, the pitcher has a great arsenal at his disposal in the variation of location, velocity, movement, and arm position (see [[list of baseball pitches|types of pitches]]). Most pitchers attempt to master two or three types of pitches; some pitchers throw up to six types of pitches with varying degrees of control. Common pitches include a [[fastball]], which is the ball thrown at high speed; a [[curveball]], which is made to curve by rotation imparted by the pitcher; a [[change-up]], which seeks to mimic the delivery of a fastball, but arrives at significantly lower velocity; a [[Split Finger Fastball#Split-finger fastball|splitfinger fastball]], which attempts to mimic the delivery of a fastball, but has slight topspin rotation allowing the baseball to sink as it approaches the batter due to the position of the index finger and middle finger being "split" on the baseball; a [[Slider (baseball)|slider]], which is made to curve laterally by rotation imparted by the pitcher; a [[knuckleball]], which is held either by the knuckles closest to the nails or by the nails themselves letting the pitcher throw a baseball with little or no spin on the ball allowing the baseball to move in any direction; a [[Vulcan changeup]], which seeks to mimic the delivery of a fastball, but arrives at a significant lower velocity due to the pitcher holding the baseball with the middle and ring fingers slightly apart; a [[circle changeup]], which is held in the palm of the hand with the index finger curled around the side of the baseball, allowing the pitcher to mimic the delivery of a fastball, but arrives at a significantly lower velocity.

To illustrate pitching strategy, consider the "fastball/change-up" combination: The average major-league pitcher can throw a fastball around {{convert|90|mph|kph}}, and a few pitchers have even exceeded {{convert|100|mph}}. The change-up is thrown somewhere between {{convert|75|and|85|mph}}. Since the batter's timing is critical to hitting a pitch, a batter swinging to hit what looks like a fastball, would be terribly fooled (swing and miss, hopefully) when the pitch turns out to be a much slower change-up.

Some pitchers choose to throw using the '[[Submarine (baseball)|submarine style]],' a very efficient sidearm or near-underhand motion. Pitchers with a submarine delivery are often very difficult to hit because of the angle and movement of the ball once released. [[Walter Johnson]], who threw one of the fastest fastballs in the history of the game, threw sidearm (though not submarine) rather than a normal overhand. True underhanded pitching is permitted in Major League Baseball. However, it is difficult to generate enough velocity and movement with the underhand motion. Among modern Major League pitchers, [[Chad Bradford]] had the closest to an underhand delivery, with his knuckles sometimes scraping the ground. However, he is still usually considered a "submarine" pitcher.

One example of variation in professional leagues is the use of a [[pitch clock]], which some leagues use to speed up the game's [[pace of play]]. The rule was first implemented in [[college baseball]] in [[2010 Southeastern Conference baseball tournament|2010]], and added to certain levels of [[Minor League Baseball]] in 2015.<ref>{{cite web|url=http://content.usatoday.com/communities/gameon/post/2010/05/pitch-clock-for-baseball-experiment-begins-in-sec/1|title=Pitch clock for baseball? Experiment begins in SEC|work=USAToday.com |date=May 26, 2010|access-date=October 12, 2015|archive-url=https://web.archive.org/web/20110824012339/http://content.usatoday.com/communities/gameon/post/2010/05/pitch-clock-for-baseball-experiment-begins-in-sec/1|archive-date=August 24, 2011|url-status=live}}</ref><ref>{{cite web|title=Pitch clock for Double-A, Triple-A use|url=https://www.espn.com/mlb/story/_/id/12172716/mlb-use-pitch-clock-double-triple-games|website=[[ESPN]]|date=15 January 2015|access-date=October 11, 2015|archive-url=https://web.archive.org/web/20151002220143/http://espn.go.com/mlb/story/_/id/12172716/mlb-use-pitch-clock-double-triple-games|archive-date=October 2, 2015|url-status=live}}</ref><ref>{{Cite web |url=http://www.nola.com/tulane/index.ssf/2011/03/ncaa_rules_for_college_basebal.html |title=NCAA rules for college baseball are designed to speed up the game |date=7 March 2011 |access-date=2015-10-12 |archive-url=https://web.archive.org/web/20160125183902/http://www.nola.com/tulane/index.ssf/2011/03/ncaa_rules_for_college_basebal.html |archive-date=2016-01-25 |url-status=live }}</ref> The clock was introduced to Major League Baseball starting in the [[2023 Major League Baseball season]], establishing a 15 second time limit between pitches with the bases empty, and 20 seconds with at least one baserunner, as well as an automatic ball for violations of the clock.<ref name="manfred">{{cite news|url=https://www.mlb.com/news/mlb-2023-rule-changes-pitch-timer-larger-bases-shifts |title=Pitch timer, shift restrictions among announced rule changes for '23 |first=Anthony |last=Castrovince |publisher=[[MLB Advanced Media]]|location=[[New York City|New York]] |date=September 9, 2022 |access-date=September 9, 2022}}</ref> The rule does not exist in other top-level leagues, such as Japan's [[Nippon Professional Baseball]] (NPB), where there exists some resistance to its adoption.<ref>{{cite news |title=What is good about Japanese baseball? A Canadian Hanshin fan's wish: "Don't chase all the new MLB rules." |url=https://www.daily.co.jp/tigers/trevor/2023/05/15/0016349855.shtml |agency=[[Daily Sports (Japanese newspaper)|Daily Sports]] |date=May 15, 2023 |language=ja}}</ref> South Korea's [[KBO League]] said in 2023 that it would implement a pitch clock "at the earliest possible date."<ref name="yonhap">{{cite news |title=KBO to bring back full-time manager for nat'l team, adopt pitch clock |url=https://en.yna.co.kr/view/AEN20230720003500315 |agency=Yonhap News Agency |date=July 20, 2023}}</ref>