Complex sentence: His highest scoring average was when he averaged 19.5 points per game during the 1974-1975 campaign in which he was traded to the Los Angeles Lakers mid-season after playing with the Milwaukee Bucks from the 1970-1971 season.
Split into simpler sentences: His highest scoring average was 19.5 points per game, during the 1974-1975 campaign. Part of the way through that season he was traded to the Los Angeles Lakers after playing with the Milwaukee Bucks from the 1970-1971 season.