Ballistically, a cutter is supposed to be something that approaches fastball speed with a quick horizontal break of about 4-5 inches at the end. Problem is, ballistically that’s also a slider if you understand it ambiguously enough. And ya know, that’s the level of detail sports reporters and game announcers delve to…the ambiguous. So I have been in denial for about 10 years, I was convinced the cutter was just a slider, a new name for something that has existed for a century. Well, you come to appreciate the distinction is a matter of degree with the physicality of the wrist and hand action on the ball.
It’s fair to say, I think, that with a slider you try to snap the heck out of the ball to get that horizontal frisbee side spin. If you’re a righthander, you turn your wrist / hand right to left as you’re releasing. You get right to left side spin, and the ball will break down and away from a right handed batter. It’s somewhat violent, and they have said forever that sliders are hard on the arm.
With the cutter, you hold the ball off center, with your fingers riding a couple ticks to the right on the ball. This bit of say asymmetrical finger contact as you release somewhat naturally creates that slider type side spin. You have to develop a feel for it I’m sure. It’s not very hard spin though, but you can make it more assertive with a mild wrist snap. As pitcher you’re just looking to put enough spin on it to make it ripple about 10-15 feet away from the plate. Similar effect (but not identical) as a slider, less effort, less wear and tear. Same results if you do it right, batter can’t keep with the late movement and doesn’t contact with fat part of bat, grounds out etc.