1. Similarity and Deception: A curve thrown within 15mph of one’s fastball won’t “pop” out of the hand. This is an interesting phenomenon – on almost all slow curves, the ball will appear to pop up out of the hand immediately upon release, and batters can easily pick this up. Curves that are thrown harder tend to take the same flight pattern as a fastball out of the hand, eliminating this tell for the batter, forcing the hitter to wait longer before deciding what the pitch is and where it will end up.
2. Sharper and later break: This is just physics – the harder the ball is thrown with forward spin and the faster it will move when it does start to break, and the extra velocity will help it travel farther before breaking. The pitch won’t break as far, but any hitter will tell you that a short, sharp curve is more difficult to square up than a long, loopy one.
3. Shorter Reaction Time: Duh. Throw it harder and their reaction time is shortened, making any pitcher harder to hit.

The Ol’ Vida Blue

The first reason is probably the least mainstream, and is something that hitters start to pick up on when they reach the more elite ranks. High school hitters don’t pick up on much unless they’re special, but college and pro ones do. That slow curve almost always appears to start going upward out of the hand, which makes it look larger, and tells the hitter that a fastball is not on its way. It is something that is hard to describe, but is easily seen from the batter’s perspective.

The solution to this is to throw the pitch harder. For those who throw it 20 miles per hour slower than a fastball, getting to that 17mph difference will feel like the ball is coming out very fast. Those first few bullpens will be filled with curves in the dirt as the arm speeds up faster than the grip is used to. But, over time, that 17 will feel normal, and 15 will be possible. Falling somewhere between 12-15mph slower is where almost all curves are thrown at the pro level, and one’s goal should be to get to the point of throwing the curveball with the exact same intentional speed as the fastball. This will maximize all of the off-speed benefits the pitch has to offer.

So go watch some games, and pay attention to the numbers. Aside from Ted Lilly and a few others, most curves will be at or under that 15mph threshold. The site fangraphs.com is pretty cool, as they show you pitch speeds for all major league pitchers. Check out Justin Verlander’s chart here.

Maybe if it gets good enough, someone will compare your curve to Vida Blue, who apparently threw a pretty nasty one. In the immortal words of my friend Joe Michalski… “Give ‘em the ol’ Vida Blue Hammer!”

This is a drill that I have been doing for about 9 years now.  I learned it from my friend Duane Rhine, who taught me the curveball that got me into college.  My hammer was the only reason my 78-81 arm ever saw the mound as a freshman, and this drill helps tremendously to get the spin and consistent release down.

The point of the bucket? Well, that’s your “strike” release point.  Don’t expect the ball to break at such low velocity; just work on getting tight spin from your grip and follow through. Learn to nail that bucket on a consistent basis and you will have no trouble spotting up that curve in game situations.  It’s all about repetition with proper mechanics.