Michael MacBeath talks about how balls are tracked. I’m waiting to see if witches are involved. 🙂

Update:When a fly ball is hit straight at a fielder, it appears to rise at a constant velocity. When the velocity changes, ball is no longer coming right at you. Same holds for balls hit to the side, fielers keep ball at a constant angle.

Dogs use same methods.

Fielders use the same straight line constant optical speed to catch grounders.

Can tell where ball is going by watching all fielders.