Who invented the double switch?

Answer 1

The double switch is at least a century old; because early records are sparse, it is probably impossible to pin down who first used it. An early documented example took place in the game played by the New York Highlanders (the future Yankees) on August 2, 1906 in Detroit. Player-manager Clark Griffith brought himself in as a relief pitcher in the eighth inning, but put himself in the number eight spot in the order replacing the catcher; at the same time he brought in a new catcher in the pitcher's number nine spot.