Complex sentence: Henry Louis "Lou" or "Buster" Gehrig (June 19,1903--June 2,1941) was an American baseball first baseman who played 17 seasons in Major League Baseball (MLB) for the New York Yankees, from 1923 through 1939.
Split into simpler sentences: Henry Louis "Lou" or "Buster" Gehrig (June 19,1903--June 2,1941) was an American baseball player. He was a Major League Baseball (MLB) first baseman who played 17 seasons for the New York Yankees, from 1923 through 1939.