This is a children's book, in the same vein as Narnia, and Harry Potter. Boy discovers he is the hero, doesn't think he can do it, does. With talking animals. What's different about this is that it's all about American mythology and fairy stories, and it's also written by a Pullitzer prize winning author. So you already know it's not as badly written as Potter, or as upper-middle-class-Englishy as Narnia.
You don't need to know what a short-stop is to enjoy the book, the baseball parts were exciting and interesting even to someone who has never been to the bottom of the ninth. That's near the end of the game, you know. See, my knowledge of the game has increased enormously. The fantastic parts of the story are fun, believable and made me want to visit the world he created. Well worth reading, and I hope it gets to be as well-loved as Potter and the Narnia books.
Oh, it's also got a bigfoot, called Taffy. Come on, when's the last time you read a book with a sasquatch as one of the characters? Never, that's when.