Mickey Kaline Sr. (pronounced "Kay-Line") is a fictional character in the Hey Arnold! TV Series. He is Arnold's favorite baseball player who plays for the Hillwood Black Sox. He retires after hitting a home run on the final swing of his career, which Arnold catches and gives back to him. Early in his career he was severely injured by a player named Johnny "Target Practice" Banks, who suffered from "Dangerous Lumber." Mickey wore number three for the Hillwood Black Sox. He bats and throws right-handed, and played first base at least once during his career.