I was unfamiliar with baseball before listening to it as an audiobook, and after listening to it I'd still say I'm unfamiliar with the sport, but I know more about it now!
It's a good sport-focused mystery involving teens, and I think the book fits best with an audience of about 13-16 years of age. Not that anyone older won't enjoy it, but considering the high school setting, simplistic plot, and how quickly you can get through this book (about an hour), it's a good read for a kid during recess and lunch. It has a satisfying end and while it's a simple mystery it has enough curves to make it enjoyable.