How Illegal Formations Work in the NFL Explainer
At the snap, an NFL offense must have at least seven players on the line of scrimmage. The remaining players must be in the backfield. Officials judge alignment by body position relative to the ball and line, not by the diagram a team intended to run.
Eligible receivers must occupy both ends of the offensive line, while the players between those ends are ineligible by position. A normally ineligible numbered player can report as eligible, but the formation still has to place that player at an eligible spot and the referee announces the report.
A wide receiver who lines up too far back can leave only six players on the line. A slot player who creeps too far forward can cover an end receiver and make that receiver ineligible. Small differences in alignment therefore change both formation legality and passing eligibility.
Illegal formation is normally a five-yard penalty. Because the foul exists at the snap, the play can continue and the defense may choose the result or the penalty. Players check with sideline officials before the snap, but responsibility for a legal set remains with the offense.
At least seven.
The players on the two ends, assuming their numbering and reports are legal.
Five yards.
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