Innings pitched
In baseball, innings pitched (IP) are the number of innings a pitcher has completed, measured by the number of batters and baserunners that are put out while the pitcher is 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 34 1⁄3 innings, 72 2⁄3 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.
The only active players in the top 100 all-time at the end of the 2009 season were Tom Glavine (ranked 30th with 4,413 1⁄3 IP), Randy Johnson (ranked 38th with 4,135 1⁄3), Jamie Moyer (ranked 45th with 3,908 2⁄3) and John Smoltz (ranked 74th with 3473). This is because over time, innings pitched has declined. Several factors are responsible for this decline:
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