DEFENSE / COACHING-SOURCE CHECKED
Cover 3 Sky · 4–3
Three deep defenders, four underneath defenders, and a four-player rush, drawn with the safety rotating to the right flat.
Documented coaching concept; original teaching illustration. No game-film verification is claimed.
Four linemen, three linebackers, two corners, and two safeties account for eleven defenders. Sky is to the offense’s right. The offense is an eleven-player 2 × 2 reference formation. Shaded areas communicate responsibility, not immovable boundaries.
01 / Every player accounted for
Eleven players. Eleven assignments.
| Player | Job | Source or teaching assumption |
|---|---|---|
| CL | Protect the left outside deep third. | Source coverage role. Maintain depth relative to threatening routes. |
| CR | Protect the right outside deep third. | Source coverage role. The picture shows a drop landmark, not a fixed endpoint. |
| FS | Rotate to the deep middle third. | Source role for the safety away from the Sky side. |
| SS | Rotate toward the right flat. | Source Sky-side safety role in this selected variant. |
| W | Expand to the left flat. | Source role for the outside linebacker away from Sky. |
| B | Cover the right hook/curl area. | Source Sky-side linebacker role. B labels that backer in this drawing. |
| M | Cover the left hook/curl area. | Source middle-linebacker role away from Sky. |
| E1 | Rush the left edge while maintaining the chosen contain lane. | MJ teaching rush lane; the cited source specifies the front, not this exact rush call. |
| T1 | Rush the left interior lane. | MJ teaching lane against the shown alignment; no stunt is drawn. |
| T2 | Rush the right interior lane. | MJ teaching lane against the shown alignment; no stunt is drawn. |
| E2 | Rush the right edge while maintaining the chosen contain lane. | MJ teaching rush lane. All four rush paths are illustrative, not film tracks. |
This is a simplified spot-drop teaching picture, not a complete pattern-match installation. Route distribution, run fits, receiver releases, formation checks, and staff rules change how defenders execute. It does not identify a real opponent’s coverage from alignment alone.
02 / Academic model → football question
How quickly is the available space changing?
average closing speed = (initial separation − final separation) / elapsed time
Use synchronized field positions for the same two players at the start and end of an interval. A positive result means their separation decreased on average. For example, 8 yd becoming 4 yd over 1 s gives 4 yd/s average closing speed.
That scalar average does not establish a future collision or interception. Direction, acceleration, reachable space, and the ball’s arrival time still matter.
Try your marked clip in the lab ↗03 / What was checked
Trace the concept to its source.
Joe Mohr / SparkQB · coaching reference ↗
The source establishes this 4–3 Sky variant and all seven coverage roles. MJ supplies the teaching coordinates and four uncomplicated rush lanes; these lanes are not represented as a sourced team call.
Checked September 25, 2026: player count, declared alignment, complete assignment list, drawing-to-table consistency, and the distinction between sourced concept rules and our teaching assumptions. This is a source review, not coach certification or demonstrated game performance.
The original drawings are by MJ Physics Engineering. The cited coaches and publishers do not endorse this site.