John Fox assembled an impressive coaching staff in his first season as head coach of the Chicago Bears. Adam Gase (offensive) and Vic Fangio (defensive) have been excellent coordinators, as they've both played crucial roles in Fox's rebuilding project.

However, as is always the case with successful coordinators, Fox knows he could lose Gase and/or Fangio to head coaching positions after this season.

Via Rich Campbell of the Chicago Tribune:

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Bears HC John Fox, asked if he's bracing to have to find new coordinators: "It never stays the same. ...Business as usual."

— Rich Campbell (@Rich_Campbell) December 31, 2015

Gase, 37, came over from the Denver Broncos with Fox. He has done a tremendous job transforming quarterback Jay Cutler into an efficient passer. Heading into Week 17, Cutler has only thrown eight interceptions. He threw 18 last season.

Fangio, 57, was previously with the San Francisco 49ers, where he was passed over for the head coaching job after Jim Harbaugh departed (his D-line coach Jim Tomsula was picked for the job). He transitioned Chicago's defense from a 4-3 to a 3-4 scheme, and the unit now ranks 16th in the NFL after ranking 30th last year.

If Gase and Fangio end up taking head-coaching opportunities, Fox will be hard-pressed to find suitable replacements.