John Jacob Atz, born Jacob Henry Atz (born July 1, 1879, in Washington, DC - May 22, 1945) was a second baseman for the Washington Senators (1902) and Chicago White Sox (1907-09). Atz was one of the first Jewish players in Major League Baseball. Early in his career he changed his name from Zimmerman to Atz. After his short tenure in the Major Leagues, he became one of the most successful Minor League Baseball managers in history. He died in New Orleans, Louisiana.