Say what you will about Indianapolis Colts defensive coordinator Lou Anarumo, but he has done a good job with a banged-up Indy defense this season. While his career numbers don't impress, his scheme has been effective against really good quarterbacks, such as Patrick Mahomes.
Should Anarumo be a head coach? That is up for some NFL team to say, of course. The coach has been a defensive coordinator in the league for eight seasons, and in none of those seasons has his unit ranked higher than 16th in yards allowed. In six of those seasons, his defenses have ranked 23rd (which is this year) or worse.