The forkball is gripped in between the index and middle fingers. The fingers are spread out very wide as the ball fits in between these two fingers. It helps if you have long fingers and is a difficult pitch to learn if you are young and still growing.
Start with your index and middle fingers along the seams like a two-seam fast-ball. Spread your fingers out as far as possible around the ball. The ball should be jammed further between your index and middle fingers than in a split-fingered fastball.
When releasing the ball, snap your wrist. This will cause the ball to have a slight forward spin instead of a backspin. The forward spin is what causes the ball to tumble down the strike zone.
Forkball grip (side view)
The ball action of the forkball is the bottom dropping out of it. Or it slightly tumbles at the end. The rotation is minimal and you can almost see the seams of the ball. The ball is split by the index and middle finger, and the thumb supports it from underneath. The ball is thrown like a fastball only with a slightly stiff wrist. The ball comes out of the hand on the same plain as the fastball and is hard to pick up. It is usually thrown hard like a fastball but will have a little less velocity.
On the other side of the coin, some pitchers will use it as an off speed pitch with a considerable amount of less velocity. The forkball can also be caused to break down and in to a right hander, or down and away by applying finger pressure as you release the ball.
This is a tough pitch to master and I don't recommend it early on in your career. You need to remember that mastering the fastball and location is at the top of the list. Once you can do that, than you can apply other tools to your arsenal. But don't forget the basics, learn your pitching mechanics, learn the fastball, and learn location. The rest will come.
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