How do I tell my coach I want to play short stop?

Here's the story. I'm on an all star team and I've never played for this coach. He was asking what positions we like and I said shortstop. We happen to have another shortstop on the team that when he is lucky enough to field the ball cleanly, he will normally throw it away. I know I can do better. He misses the easy ones, has no accuracy, and no speed. He has a good bat but I think we should swap positions. I think he should play 3rd (where I currently play) and I think I should play shortstop. Even when his dad coached me and him his dad put me at shortstop. Not to mention the other kid always goofs off at practice. I never goof off. I love baseball and take it seriously. It saddens me to see a kid who I could do better than just goof off thinking he's a lock to play shortstop. I just don't know what to tell the coach. I try playing extra hard so the coach might notice me but he normally doesn't care it seems like. What should I do or say to get the coach to put me at shortstop.