It's a good start. The action is too too fast to tell what's going on. There should be a slight pause (more of a pause) between the time he lets go of the ball, to the time he gets hit so it's not one action, but two. That give the viewer time to process what's going on.
Also, there's not really much of a story, so it's not really ready to be submitted. It's a great example of what you'll have for us eventually, so definitely, keep at it!