Where will the guy who replaces him come from?
So far, the candidates are all coordinators in the NFL. But I was curious where head coaches in the NFL originated. What positions did they coach before they moved up the ranks?
Some moved around a lot, some worked exclusively at one spot. Some were tougher to categorize than others and I leaned a bit on what they played if I was tie-breaking.
My breakdown of the NFL coaches who were in the league in 2013 and remain in their posts:
Defensive backs (6): John Fox (Broncos), Chuck Pagano (Colts), Dennis Allen (Raiders), Mike Tomlin (Steelers), Jeff Fisher (Rams), Pete Carroll (Seahawks).
Linebackers (5): Marvin Lewis (Bengals), Gus Bradley (Jaguars), Bill Belichick (Patriots), Mike Smith (Falcons), Ron Rivera (Panthers).
Offensive line (3): Doug Marone (Bills), Andy Reid (Chiefs), Joe Philbin (Dolphins).
Defensive line (1): Rex Ryan (Jets).
Running backs (1): Chip Kelly (Eagles).
Special teams (1): John Harbaugh (Ravens).
The Titans' interviews so far were with two guys with a quarterback background in Jay Gruden (who's now off the market) and Jim Caldwell and one with a defensive backs background in Mike Zimmer. Next up is Ken Whisenhunt, who has a tight ends background.
Others who I think will be interviewed: Dan Quinn (defensive line) and Rich Bisaccia (special teams).