Two Down Full Base

Based on the children's book by Sunada Hiroshi.

Musuke "Shorty" Sato is a shortstop for the local junior baseball team, the Eggs, who is asked by his mother to look after some money for her. He foolishly lends it to Tower and Dump, the school bad-boys, and must enlist the help of the pitcher's pretty little sister.

(Source: The Anime Encyclopedia)