Martin John Krug (10 September 1888 – 27 June 1966) was a major league infielder with the Boston Red Sox (1912) and Chicago Cubs (1922). Born Martin Johannes Krieg in Koblenz, German Empire, his parents immigrated to the United States, and he was raised in Cleveland, Ohio. He was a backup shortstop for the 1912 World Series champion Red Sox, but had little opportunity to play behind starter Heinie Wagner. He was primarily a third baseman for the 1922 Cubs.