Malvyn John "Mally" Nydahl, sometimes spelled Nydall (November 24, 1906 – May 27, 1979), was an American football, baseball, and basketball player and orthopedic surgeon.

[3] Grantland Rice rated Nydahl as "one of the greatest backs ever to come out of the Middle West".

[3][5][6] Nydahl played minor league baseball for several years after graduating from Minnesota, including stints with the Davenport Blue Sox (1929, 1931), Denver Bears (1932), Omaha Packers (1933), Oklahoma City Indians (1933), and Elmira Red Wings (1933).

He appeared in 27 NFL games, 19 as a starter, scored four touchdowns, and kicked three extra points.

[9] Nydahl used his earnings as a professional football player to put himself through medical school.