A Softball Halloween Costume? Tutu? Dress? Creativity?

I want to try and make a softball costume. Im gonna wear knee highs, and cleats. I want to try and take a sotball jersey and make it into a dress. A poofy one. Not to much poof, though, Im gonna try and put a tutu under it. Any idea how to change the shirt into a dress? How to make a tutu? I know how, but how to make it POOOFIIIERRR. lol. and Any other idea? Thanks <3