It might be too early to crown a coach of the year already but Cardinals Head Coach Bruce Arians seems like a no brainer at this point. The Cardinals are currently 7-1.
The Cardinals suffered injuries to almost all of their key players and their one loss came when they had to use their 3rd string QB. Despite using backups throughout the season, the coaching staff has been able to field a competitive team week in and week out.
Since leaving Pittsburgh, Arians went 11-5 as an interim coach for the Colts. After leaving for the Arizona job, he has gone 17-7 in his Cardinals career. Arians also won coach of the year in 2012, so if he wins it this year, he will have won twice in three seasons with different teams, which has never been done before.