It looks like a fastball, but it's not

When I'm working with junior high and high school pitchers, we work quite a bit on the changeup.

I feel it's one of the most important pitches you can own because it places minimal stress on the arm and can frustrate a lot of hitters.

In collegiate baseball, for instance, most hitters, particularly those in the middle of the lineup, are looking for the fastball. They're looking for fastball arm speed, fastball rotation, and a fastball release point. 

The changeup is the only pitch that "looks" like a fastball to a hitter: it comes out of the hand at the same spot, it's thrown with the same arm speed, etc.

I'd say 8 or 9 times out of 10, you're ability (and confidence) to throw a changeup will enable you to get the hitter to swing through the pitch or take it, both of which are to your advantage. So why not start working on the pitch now if you don't have one? And if you do have a changeup, now's a good time to make it better.

That's what my high school pitchers are doing. You'll be happy with the results.