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...

, innings pitched (IP) are the number of inning

Inning

Inning is a municipality in the district of Erding in Bavaria in Germany....

s a pitcher

Pitcher

In baseball, the pitcher is the player who throwsthe baseball from the pitcher's mound toward the catcher to begin each play, with the goal of retiring a batter, who attempts to either make contact with the pitched ball or draw a walk. In the numbering system used to record defensive plays, the...

 has completed, measured by the number of batters and baserunners that are put out while the pitcher on the pitching mound in a game. Three outs made is equal to one inning pitched. One out counts as one-third of an inning, and two outs counts as two-thirds of an inning. Sometimes, the statistic is written 34.1, 72.2, or 91.0, for example, to represent innings, innings, and 91 innings exactly, respectively.

Runners left on base by a pitcher are not counted in determining innings pitched. It is possible for a pitcher to enter a game, give up several hits and possibly even several runs, and be removed before achieving any outs, thereby recording a total of zero innings pitched.

Decline

The only active players in the top 100 all-time at the end of the season were 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...

 (ranked 30th with IP), Randy Johnson

Randy Johnson

Randall David Johnson , nicknamed "The Big Unit", is a former Major League Baseball left-handed pitcher. During a 22-year career, he pitched for six different teams....

 (ranked 38th with ), Jamie Moyer

Jamie Moyer

Jamie Moyer is an American professional left handed baseball pitcher who is currently a free agent. At the time of his last game to date , he was the oldest player in the major leagues and had the most wins, losses, and strikeouts of any active Major League pitcher...

 (ranked 45th with ) and John Smoltz

John Smoltz

John Andrew Smoltz is an American former Major League Baseball pitcher and active sportscaster. He is best known for his prolific career of more than two decades with the Atlanta Braves, in which he garnered eight All-Star selections and received the Cy Young Award in 1996...

 (ranked 74th with 3473). This is because over time, innings pitched has declined. Several factors are responsible for this decline:

• From 1876–1892, pitchers threw from fifty feet and exerted less stress on their arms (also pitchers often threw underhand in this era). In this era, innings pitched totals of 600 innings were not uncommon.
• In 1892, pitchers moved back to the current distance of sixty feet, six inches. However, they still often threw 400 innings in a season. This was because the home run
  Home run
  In baseball, a home run is scored when the ball is hit in such a way that the batter is able to reach home safely in one play without any errors being committed by the defensive team in the process...
  
   was far less common and pitchers often conserved arm strength throughout the game.
• From 1920 to the 1980s, the four-man pitching rotation was well established. Pitchers could no longer throw 400 innings in a season, as the home run
  Home run
  In baseball, a home run is scored when the ball is hit in such a way that the batter is able to reach home safely in one play without any errors being committed by the defensive team in the process...
  
   meant a run could be scored at any time. The league leader in innings pitched often threw somewhat more than 300 innings. Occasionally, innings pitched would spike, as in the early 1970s, when Wilbur Wood
  Wilbur Wood
  Wilbur Forrester Wood, Jr. is a former knuckleball pitcher in Major League Baseball for the Boston Red Sox, Pittsburgh Pirates, and most notably the Chicago White Sox, where he got 163 of his 164 wins...
  
   pitched innings in and then innings in .
• From the 1980s to the present, the four-man rotation was replaced with the five-man rotation, with a weak fifth man who would often be skipped on off days. Also, managers starting using their bullpen
  Bullpen
  In baseball, the bullpen is the area where relief pitchers warm-up before entering a game. Depending on the ballpark, it may be situated in foul territory along the baselines or just beyond the outfield fence. Also, a team's roster of relief pitchers is metonymically referred to as "the bullpen"...
  
  s more and more, accelerating the decline in innings pitched. Today, rarely more than a few pitchers pitch more than 250 innings in a season.

All-time leaders

Rank	Player	Innings pitched
1	Cy Young Cy Young Denton True "Cy" Young was an American Major League Baseball pitcher. During his 22-year baseball career , he pitched for five different teams. Young was elected to the National Baseball Hall of Fame in 1937...
2	Pud Galvin Pud Galvin James Francis Galvin , nicknamed "Pud", "Gentle Jeems", and "The Little Steam Engine", was an American National Association and Major League Baseball pitcher. He was Major League Baseball's first 300-game winner...
3	Walter Johnson Walter Johnson Walter Perry Johnson , nicknamed "Barney" and "The Big Train", was a Major League Baseball right-handed pitcher. He played his entire 21-year baseball career for the Washington Senators...
4	Phil Niekro Phil Niekro Philip Henry Niekro , nicknamed "Knucksie" because of his usage and skill level with the knuckleball, is a former Major League Baseball pitcher. He was inducted into the Baseball Hall of Fame in 1997....
5	Nolan Ryan Nolan Ryan Lynn Nolan Ryan, Jr. , nicknamed "The Ryan Express", is a former Major League Baseball pitcher. He is currently principal owner, president and CEO of the Texas Rangers....	5,386
6	Gaylord Perry Gaylord Perry Gaylord Jackson Perry is a former Major League Baseball right-handed pitcher. He pitched from 1962-1983 for eight different teams in his career. During a 22-year baseball career, Perry compiled 314 wins, 3,534 strikeouts, and a 3.11 earned run average...
7	Don Sutton
8	Warren Spahn Warren Spahn Warren Edward Spahn was an American Major League Baseball left-handed pitcher. He played his entire 21-year baseball career in the National League. He won 20 games each in 13 seasons, including a 23-7 record when he was age 42...  *
9	Steve Carlton Steve Carlton Steven Norman Carlton , nicknamed "Lefty", is a former Major League Baseball left-handed pitcher. He pitched from 1965-1988 for six different teams in his career, but it is his time with the Philadelphia Phillies where he received his greatest acclaim as a professional and won four Cy Young Awards...  *
10	Grover Cleveland Alexander Grover Cleveland Alexander Grover Cleveland Alexander , nicknamed "Old Pete", was an American Major League Baseball pitcher. He played for the Philadelphia Phillies, Chicago Cubs, and St. Louis Cardinals and was elected into the Baseball Hall of Fame in 1938.-Career:Alexander was born in Elba, Nebraska, one of thirteen...	5,190
11	Kid Nichols Kid Nichols Charles Augustus Nichols , better known as Kid Nichols, was a Major League Baseball pitcher. Admired for his steadfast consistency year-in and year-out, Nichols won 361 games, the 7th highest total in major league history...
12	Tim Keefe Tim Keefe Timothy John "Tim" Keefe , nicknamed "Smiling Tim" and "Sir Timothy", was an American Major League Baseball pitcher. He was one of the most dominating pitchers of the 19th century and posted impressive statistics in one category or another for almost every season he pitched...
13	Greg Maddux Greg Maddux Gregory Alan Maddux , nicknamed "Mad Dog" and "The Professor", is a former Major League Baseball pitcher. He was the first pitcher in major league history to win the Cy Young Award for four consecutive years , a feat matched only by Randy Johnson...
14	Bert Blyleven Bert Blyleven Bert Blyleven is a former Major League Baseball pitcher who played from to , and was best known for his curveball. Blyleven was inducted into the Baseball Hall of Fame in 2011...	4,970
15	Bobby Mathews Bobby Mathews Robert T. Mathews was an American right-handed Major League Baseball pitcher for twenty years beginning in the late 1860s. He is credited as being one of the inventors of the spitball pitch, which was rediscovered or reintroduced to the major leagues after he died. He is also credited with the...
16	Roger Clemens Roger Clemens William Roger Clemens , nicknamed "Rocket", is a former Major League Baseball pitcher who broke into the league with the Boston Red Sox, whose pitching staff he would help anchor for 12 years. Clemens won seven Cy Young Awards, more than any other pitcher. He played for four different teams over...
17	Mickey Welch Mickey Welch Michael Francis Welch Born as Michael Francis Walsh , nicknamed "Smiling Mickey", was a Major League Baseball pitcher. He was the third pitcher to accumulate 300 career victories. Welch was born in Brooklyn, New York, and played 13 seasons in the major leagues, three with the Troy Trojans, and 10...	4,802
18	Tom Seaver Tom Seaver George Thomas "Tom" Seaver , nicknamed "Tom Terrific" and "The Franchise", is a former Major League Baseball pitcher. He pitched from 1967-1986 for four different teams in his career, but is noted primarily for his time with the New York Mets...
19	Christy Mathewson Christy Mathewson Christopher "Christy" Mathewson , nicknamed "Big Six", "The Christian Gentleman", or "Matty", was an American Major League Baseball right-handed pitcher. He played his entire career in what is known as the dead-ball era...
20	Tommy John Tommy John Thomas Edward John Jr. is a former left-handed pitcher in Major League Baseball whose 288 career victories rank as the seventh highest total among left-handers in major league history... *
* Pitched left-handed Active players in bold Through 2009 season

External links

• All-time innings pitched leaders