After the war, Sieradzki enrolled at Michigan State College (later known as
Michigan State University) and played college football at the fullback position for the Spartans in 1946 and 1947. He also played college baseball for Michigan State. In June 1948, Sieradzki signed a combined football and baseball contradt with the Ne York Yankees of the
American League and
All-American Football Conference (AAFC). He also played for
Brooklyn Dodgers of the AAFC during the 1948 season. He appeared in three AAFC games, two for the Yankees and one for the Dodgers. ==Family and later years==