Of the triad at the very core of baseball (batting, fielding, and pitching), the subject of pitching is far and away the most complex and subtle. This is true not just from the perspective of playing and coaching, but for the umpire as well. There are a large number of rules, and many of these are heavily nuanced.
Areas like working the plate, calling balls and strikes, and particularly seeing and calling balks, take time and experience. Even a seemingly silly question like "When is a pitcher not a pitcher?" is actually an important and meaningful question.
The topic of pitchers and pitching is so large, in fact, that we cover it over the span of four articles. The present article, The Pitcher, is first in the series. The remaining three are:
What is a pitcher?
It sounds like a stupid question, but it's not. In fact, it is extremely important to understand what a pitcher is, and to further understand when a pitcher is a pitcher and when he is not. Read on.
The answer to the question "What is a pitcher?" is at first blush pretty obvious, and it's the one we find in the rule book, Definitions (pitcher): "… the fielder designated to deliver the pitch to the batter." But then we learn there's more to it, when we learn that the player who is designated in the lineup as the pitcher, when in contact with the pitching plate, is in fact a pitcher; but, when he is not in contact with the pitching plate, this player is not a pitcher but simply a fielder.
The second definition seems to contradict the first. And, in a sense, it does. On one hand, the pitcher is the player designated on the lineup to deliver pitcher; but then we learn that he's only really a pitcher when in contact with the pitching rubber, and that at all other times on defense, he's simply another fielder. What gives?
The rules of baseball, that's what gives. The distinction is there because there is a set of rules that apply to the pitcher when (and only when) he is in contact with the rubber; when not in contact with the rubber, these rules do not apply.
The matter of what a pitcher can and cannot do depends on two things. First, as we've said, it matters whether the "pitcher" is a pitcher or a fielder – that is, whether he is in contact with the rubber or not. But, second, when the pitcher is engaged with the rubber, it depends further on at what point in the pitching sequence the pitcher is.
We go into detail on the pitching positions, the pitching regulations with respect to the pitching positions, and then about balks and illegal pitches in the two companion articles, The Pitching Positions and Balks & Illegal Pitches.
The Pitcher's Mound
On a regulation baseball diamond, the pitcher's mound measures 18' in diameter. The flat area atop the diamond, called the table, measures 5 feet wide by 34 inches deep. Six inches from the front edge of the table is the pitcher's plate (also called the rubber), which measures six inches deep by 24 inches wide.
The distance from the front edge of the pitcher's plate to the rear point of home plate measures 60'-6". This distance was established in 1893 and has served baseball well for more than 120 years. The height of the mound, however, has changed – most recently in 1969, when it was lowered to its present height of 10 inches. From the front of the table, the mound slopes down such that it loses one inch of height for every foot nearer to home plate.
These dimensions are the ideal, of course, and on professional fields an army of groundskeepers do well to maintain the proper dimensions. But a pitching mound is a difficult piece of ground to maintain, and on amateur fields you are liable to see considerable variance from the norm.
One measurement that does not (or should not) change, however (and which is the most important dimension on the mound), is the distance from the front edge of the pitcher's plate to the rear point of home plate. As we said, on a regulation field (that is, 90-foot basepaths), this distance is 60'-6". This distance changes only by rule, depending on league and the age level of the players.
Following are the most common pitching and field dimensions.
- Regulation field. As we've said, on a regulation field the pitching distance is 60'-6". The distance from base to base (the base path) is 90'. Regulation fields are used in professional baseball, of course, but also in college, high school, and most youth leagues whose players are about 15 and older.
- 54/80. Pony Baseball's Pony division (13-14 year olds) play on fields whose pitching distance is 54 feet and whose base paths measure 80 feet.
- 50/70. Little League introduced a new "Intermediate" division in 2012 for players from 11-13 that uses a 50' pitching distance and 70' base paths. Cal Ripken also has a 50/70 division for 11-12 year olds, and Pony Baseball uses these dimensions for its Bronco division (11-12 year olds).
- 46/60. A pitching distance 46' (60' base path) is standard for Little League divisions where the players are 12 and under. These dimensions are also common for other youth leagues whose players are younger than 12.
Note: Umpire field mechanics on playing fields measuring 50/70 and larger tend to be consistent, so throughout we will use the term "big diamond" to refer collectively to fields that are 50/70 and larger. Mechanics on 46/60 fields, however, are quite different, so we'll refer to 46/60 fields as "small diamond."