A pitcher's total number of pitches is determined by all the pitches he throws in live game action, including strikes, unintentional balls and intentional balls.
The number of pitches thrown by a pitcher is a very important number in any baseball game. It's often used to determine when a pitcher might begin to get tired. Conversely, it often benefits a hitter to face a high number of pitches, because the more pitches he sees, the more likely he is to wear down a pitcher.
Certain pitchers are capable of throwing more pitches in a start than others, but -- for the most part -- starting pitchers begin to tire as they near the 100-pitch mark. In the mainstream media, pitch counts have grown in popularity in recent years as a tool for evaluating when a pitcher might be tiring and ready to be taken out of the game.
However, pitch counts can be a very flawed mechanism, as not every pitch puts the same strain on a pitcher's arm. Breaking balls are much more taxing than fastballs, and pitches in high-leverage situations often require greater effort. Similarly, if a pitcher throws an unusually high number of pitches (say, 30 or more) in one inning, his arm may begin to tire even if his total number of pitches isn't very high.
Pitch counts became prominent for pitchers in the 1980s. Many games taking place before then do not have records of the number of pitches thrown, but pitch counts (and innings-pitched totals for individual pitchers) were much higher before then.
Watch: Masahiro Tanaka finishes a complete game on 97 pitches.
In A Call
"pitch count," "total pitches," "pitches thrown," "tosses"