Arians now is head coach in Arizona.
Arians took charge of the Colts in late September after head coach Chuck Pagano was diagnosed with leukemia. The Colts, 2-14 the previous season, went 9-3 under Arians and made the playoffs.
Pagano coached the final game of the regular season and a wild-card playoff match.
Arians earned 36 1-2 votes from a nationwide panel of 50 media members who regularly cover the NFL. Pagano finished second with 5 1-2, while Pete Carroll of Seattle received five and Leslie Frazier of Minnesota got three.
Arians spent only one season in Indy before landing the Cardinals job.
He accepted his award Saturday night at the "2nd Annual NFL Honors" awards show on CBS saluting the NFL's best players, performances and plays from the 2012 season.
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