Strike
Three ways to get one, and only two of them involve the strike zone.
What it actually is. A strike is charged when the hitter swings and misses, when he takes a pitch the umpire judges to have passed through the strike zone, or when he hits the ball foul with fewer than two strikes. Three strikes is a strikeout. The one wrinkle everybody eventually meets is that a foul ball with two strikes is not a third strike, except for a bunted foul, which is.
What somebody who knows the game gets out of it. The three routes to a strike are not equal and separating them is how pitchers get evaluated now. A swinging strike is the pitcher beating the hitter. A called strike is the pitcher and the catcher beating the hitter and the umpire together, which is why framing became a real skill with a real dollar value. A foul is the hitter surviving. Called Strikes plus Whiffs, CSW percentage, exists because adding the first two together predicts a pitcher's future better than a strikeout total does.
The numbers worth knowing. Around a quarter of all pitches thrown are called strikes and around eleven percent are swinging strikes. A pitcher with a swinging strike rate above thirteen percent has genuine bat missing stuff; below eight percent he is living on contact and defense.
What people get wrong about it. A foul tip is not a foul ball. If the ball goes sharply and directly from the bat to the catcher's mitt and is caught, it is a strike and the ball stays live, which means it is a strikeout on the third one. A pop up that the catcher catches is simply a caught fly ball. The two get called the same thing in conversation constantly.
At Little League and travel ball. Youth zones are wider than the book, and deliberately so. An umpire at 9U who calls the professional zone produces a game of walks that nobody enjoys, so he expands it, and the hitters who succeed are the ones taught to swing at strikes rather than to hunt for the perfect pitch. Parents in the stands almost always think the zone is too big; the alternative is a two hour game with eleven walks.
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