I like the smear frames and the arcs you did for the ball! If you're looking for improvements, I would remove some of the inbetweens on the ball while it's being thrown, since it's supposed to be a very fast movement and having excess frames makes it seem slower and less smooth (ironically). I also think the pitcher could have another inbetween frame on their left hand after they've thrown the ball because there's some jarring movement going on there. But overall, I think this is a nice animation!