Complex sentence: His final.370 BA was an amazing 127-point increase over his previous year mark, leading the National League batters, and was the highest average by a right-handed hitter since Joe DiMaggio batted.381 in 1939.
Split into simpler sentences: His final.370 BA was an amazing 127-point increase over his previous year mark. He lead National League batters in batting average, and it was the highest average by a right-handed hitter since Joe DiMaggio batted.381 in 1939.