The Team Leverage and Fits Drill (shown in the video below) allows you to cross-train your defenders to develop position versatility, position depth, and scheme versatility.
Matt Furlong, Head Coach, Geneseo High School (IL). Coach Furlong was the Defensive Coordinator for Cary-Grove High School (IL) when he gave this clinic.
You can view his entire presentation, which includes three more team defensive drills, on Glazier Drive: Developing Defensive Players: Team Fundamental Drills
The purpose of the drill is to develop and evaluate overall defensive players, regardless of what position they play. The evaluation lets the coaches see the players going against each other and doing similar things to see their movemement and physicality.
It builds off circuit skills, but with the the added need for spontaneous reaction.
Team fundamental drills, circuits, and EDDs: