Grip and finger pressure are the two keys to throwing a good slider. A slider is thrown with the same arm motion and velocity as a fastball; however, the unique grip and finger pressure used to throw a slider create a late sweeping break to ultimately fool the batter.
- Get a grip
Place your index and middle fingers across the widest seams of the baseball. Tuck your thumb underneath the ball, and apply equal pressure with your thumb and middle finger. Keep your ring and pinkie finger to the side, and maintain a loose wrist.
- Wind up and deliver
Keep applying pressure with your thumb and middle finger during your windup. Focus on cutting through the baseball with your middle finger. Throw the slider as you would a fastball, maintaining the same arm motion and speed. Emphasize the cutting motion during your follow-through so that the ball rolls off your index finger to give the slider its spin.
- Apply proper mechanics
Do not snap your wrist during your release, and do not let your thumb become overly involved in the pitch. Focus on letting the spin come from your middle and index fingers. If thrown properly, the slider should move on a 2-to-8 plane for right-handed pitchers and a 10-to-4 plane for left-handed pitchers.