What does a defensive coordinator do?

An NFL defensive coordinator leads the design, preparation, and operation of the team's defense. The coordinator develops the scheme, works with defensive position coaches, prepares the weekly game plan, and plans responses to the opponent's personnel and tendencies.

Many defensive coordinators call plays during games, although a defensive-minded head coach may retain that duty. The coordinator also manages substitutions, coverage and pressure packages, situational strategy, and in-game adjustments.