To throw a cutter or cut fastball, you will throw a fastball but get a slight amount of side spin that makes the ball move in or out a few inches. You do this by moving your fastball grip (usually the 4-seam fastball grip) slightly off-center. Some pitchers bring the thumb slightly up the inside of the ball and the index and middle fingers slightly toward the outside. This gives you a pitch somewhere between a fastball and a slider, and, thrown properly, that’s how the pitch will move, like a very tight slider.

For young pitchers, though, there is a tendency to turn the hand too much toward the slider position, getting a “doorknob” action with the hand that can stress the elbow. The pitcher should leave the thumb directly under the ball and move only the fingers slightly left or right, depending on which way you want to cut the ball. As you release it, think “fastball,” and spin the ball hard with your middle and index fingers, just as you would the fastball.

If you’re a right-handed pitcher holding the ball slightly off- center to the outside part of the ball, the pitch should move a few inches away from a right-handed hitter … just enough to get it away from the barrel of the bat. Unless you have a fairly high arm angle (throw “over the top”) it will be harder to learn to make the ball move the other way, but try it. Just offset the fingers slightly to the inside, and throw with fastball action.

How To Throw A Cutter … Like Mariano Rivera

To start, you hold it like a fastball. The cutter grip is a little bit off of center. Throwing it is like a fastball, and right here at about the release point, turn over your wrist.

The idea is, it’s got fastball rotation, and at about 59 feet, it cuts into a righthander for a lefthanded pitcher. For a righthanded pitcher it cuts into a lefthander. Read More