Why the changeup is so seldom used in high school.

I think most reasonable people agree that the changeup is a great pitch. At the big league level, it might be the most lethal of all pitches when thrown correctly. Furthermore, it puts no extra strain on the arm. So, why isn't it thrown more at the high school level?

Quite simply, it isn't a great pitch in high school. The reason? Primarily, because high school pitchers don't throw the pitch in the correct count.

Changeups are effective when the batter is expecting a fastball. Hitters anticipate fastballs in advantage counts. Therefore, the changeup is best thrown in hitter advantage counts. 1-0, 2-0, 2-1, 3-1. Here's the thing, the changeup is seen as a waste pitch. It is seen as pitch that isn't mastered yet. The high school pitcher doesn't usually have command of the changeup. Why would a catcher or coach call a pitch that he doesn't have command of when the hitter already has an advantage.

Until the pitcher can throw the changeup for a strike, it isn't effective because it isn't thrown in the proper count.

Watch a MLB game. You'll notice that the changeup is thrown in hitter advantage counts. Most high school pitchers would cringe at that pitch selection. Until a pitcher gains complete confidence in that pitch it simply won't be effective.