Milton Arnold "Mickey" Haefner (October 9, 1912 – January 3, 1995) was an American knuckleball-throwing left-handed pitcher in Major League Baseball who played eight seasons from 1943 to 1950, six and a half of them with the Washington Senators (1943–49), later joining the Chicago White Sox (1949–50) and the Boston Braves (1950). His career record was 78–91, with an ERA of 3.50.

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