baseball-obsessed boy; boy who lives for baseball
Refers to a boy, typically elementary or middle school age, who is extremely passionate about baseball, often spending most of his free time playing or practicing.
He's a typical baseball-obsessed boy; after school he's always on the field.
My son lives for baseball; even on days off he practices from morning till night.
Compound of 野球 (baseball) and 少年 (boy).