Multiple balls.

One ball parented to the pitcher's hand ... when he "releases" it, scale it down and move it inside the hand so it's no longer visible.

One ball "on the fly" ... off-camera until the pitcher releases, then it snaps into position and is keyframed through its parabolic arc, snapping offscreen again just as it reaches the catcher's hand.

One ball parented to the catcher's hand ... scaled down and hidden inside the hand, which scales up and becomes visible at the moment the ball is caught.

You'll need spline breaks to pull off some of these instant changes.