A palmball is a variation of the changeup. A palmball sits deep in the pocket with ball resting on the top 1/3 of the upper palm and the four fingers simply spread out over the ball across the seams, which is similar to the four seam fastball. The thumb sits in the exact same location as the four seam fastball. Pitchers with bigger hands have a real advantage because the fingers can place additional pressure across the ball.
Coming through similar to the fastball, pitchers turn their wrists in towards the ground — or just pointing the thumb. Pitchers must have near perfect mechanics with solid command to point their thumbs towards the sky because the ball can float in the zone and land 450 feet away if done incorrectly. The action of the ball is dependent on the amount of friction and rotation, but when at its best it will drop and move towards the throwing side more than any other type of change up.