The Line of Scrimmage

Note:  Written in 1992.


When I started the process of becoming a high school football “referee” a half-dozen years ago I had to put aside a fan’s perceptions and understandings of the game and take up an official’s instead.

Everything changed. As an official I no longer “watched” the game in the same way– indeed, I didn’t watch it at all in any ordinary sense of the term. Each of the four officials (1) in a typical varsity-game crew has a specific zone of observational responsibility, and woe betide the official whose attentions stray too far from his zone. Learning not to watch the game’s center of attention — the star runningback juking his way downfield or a long pass’s graceful arc — is one of the first and most difficult transitions a novice official must make. The officiating crew must collectively watch the whole field of play, and hence a division of observational responsibility among them is essential.

The game’s language changed too. Precisely specifying what happens in a game requires knowing and consistently using a technically precise vocabulary. Even the most rudimentary concepts soon became complex, nuanced, and problematic. Consider, for instance, “the line of scrimmage.” What, after all, could be a simpler football idea? On one side of the line of scrimmage lies one team’s property; on the other side, the other’s. The scrimmage line simply marks an imaginary boundary between them, spanning the breadth of the field and running parallel to the goal line. Conceptually, a piece of cake.

Not for a football official.   

First of all, “it” doesn’t actually exist–not as a singular anyhow. The divide between team “A’s” (officialese for the offensive team) turf and team “B’s” (the defensive team) turf is defined by the football itself. Between downs, the football lies with its main axis heading up- and downfield. The ball’s two ends define two scrimmage lines–one A’s, the other B’s. That leaves a narrow band of geography–as wide as the football is long–between the two lines of scrimmage, the neutral zone. It is a foul–encroachment–for any player (save one) to place any part of his body in or beyond the neutral zone. The one player granted special dispensation is the offensive center, whose initial position “over” the ball puts his head and hands into the zone. All other players must respect the neutral zone’s inviolability.

The scrimmage line concept also involves time. The rule against encroachment applies only during the dead ball interval between plays–that is, the time between the end of the previous play and the snap that marks the beginning of the next play. But the rule does not apply to the whole dead ball interval. There is a brief period after the previous play’s termination when the neutral zone and the scrimmage lines do not exist. Obviously, it would be silly to enforce the encroachment rule while receivers were trotting back to their huddle or before officials had spotted the ball.

In fact, the encroachment rule comes into effect in two stages: The first stage commences when the referee gives the ready-for-play signal–or, as officials often refer to it, when he “chops-in.” The ready-for-play signal consists of a short whistle blast and a chopping motion with the right forearm. As it happens, chopping-in is a signal referees rather like to stylize to their own tastes–so that there are a great many ways to chop-in. No matter how it is executed, however, the ready-for-play signal indicates that the offense now has 25 seconds to snap the ball and that no player may henceforth either (a) touch the ball or an opponent or (b) be present in the neutral zone (as the rule book puts it) “to give defensive signals.” It bears noting that in this stage players are not proscribed outright from entering the neutral zone. The language of (b) gives umpires the legal wherewithal to herd defensive huddlers away from the newly spotted ball. The second stage commences “after the snapper has placed his hand(s) on the ball”–thereafter, no player (aside from the snapper) may allow any part of his body to enter the neutral zone, period.

The scrimmage line concept is operationalized quite differently for the offensive and defensive teams. The reason for the difference is that football’s rules are more detailed and demanding for the offensive team’s players than for the defensive team’s players. For instance, the rules require that the offensive team lines-up a minimum of seven players on its line of scrimmage, but the defensive team’s players may line-up anywhere they like. Only offensive players legally in the backfield or on the ends of the offensive line may catch a forward pass, but any defensive player is entitled to intercept one. Offensive interior linemen must remain motionless once they’ve put a hand on or near the ground, but defensive linemen may move all they like.

This asymmetry gives rise to an equivalent asymmetry in the care and precision with which “being on the line” and “being in the back field” are defined for the two teams. For the defensive team, being on the line is a simple matter: any player within a yard of his own line of scrimmage is considered “on the line.” For the offensive team, however, the matter is more complicated. The offensive center defines the offensive line. Other linemen can’t line-up strictly parallel to the center or they’d be guilty of encroaching (see above). Therefore, the rule holds that an offensive player is on his line when some part of his body intersects an imaginary plane defined by the center’s beltline, extending from sideline to sideline. Also, a player on the line must position his body so that his shoulders are squarely facing forward.

An offensive player not on the line is not necessarily therefore in the backfield. Whether a back is in his backfield or not is defined by his position in relation to his nearest teammate who is legally on the line. A back is legally in the backfield when no part of his body intersects the plane defined by that lineman’s beltline. In short, the rules involve two crucial beltlines: the center’s and the nearest lineman’s. There is a space between these two beltlines, and officials call it “no-man’s land.” Visualize it: If a lineman’s helmet is intersecting the plane of the center’s beltline, then the distance between that lineman’s helmet and his own beltline defines a roughly two-foot-wide no-man’s land.

An offensive player lined-up in that no-man’s land has committed an illegal procedure foul the moment the ball is snapped. The foul occurs only when the ball is snapped because until then he may move himself to a new, legal position, either on the line or in the back field. In short, offensive players must respect that there is a small buffer zone between being “on the line” and being “in the backfield” and never line-up in that zone. All this complexity ultimately derives from the fact that quite different rules govern the conduct of offensive linemen and offensive backs. Therefore the offensive team has a duty to make crystal clear to the defensive team (not to mention the officiating crew) which of its players are truly on the line and which are truly in the backfield. The no-man’s land buffer provides the rulebook’s instrumentality for defining that duty.

The scrimmage line’s importance doesn’t evaporate with the snap and the end of the dead ball interval. Passing plays, for example, must respect its location long after the snap. Fans know that passers may not throw a pass from beyond the line of scrimmage. Less generally known, perhaps, is that a passed ball must cross over the line of scrimmage for rules against pass interference to come into effect. So, for example, the would-be receiver of a sideline or a screen pass that will not cross the line of scrimmage before it is received enjoys no protection from pass interference. Such rules imply and require that an official is prepared to make judgments about whether either the passer or the passed ball crossed the line of scrimmage.

The scrimmage line retains so much importance in pass plays that it determines where one of the officiating crew will position himself during such plays. The crew’s umpire is responsible for calls relating to the line of scrimmage during pass plays. The umpire initially lines up on the defense’s side of the ball, a step or so behind the linebackers. When he sees that a passing play is unfolding, he moves forward to the line of scrimmage and stays there–in officialese, that’s his mechanic for a pass play. Thus positioned, he’s at a good spot for observing four things: (a) watching for holding by interior linemen, (b) watching for ineligible receivers who slip past him and go illegally downfield, (c) determining whether a passed ball actually crossed the line of scrimmage, and (d) determining whether the passer launched his pass beyond the scrimmage line.

Oddly enough, the passer is allowed to launch his pass from anywhere on his team’s side of B’s–that is, the defensive team’s–scrimmage line. The reason for using B’s scrimmage line rather than his own (i.e., A’s) was probably pragmatic. Once play has started, the umpire may sight down to the downmarker on the sideline to establish the scrimmage line’s location. Since the downmarker is always set at the forward end of the ball, it defines B’s, not A’s, line of scrimmage. Therefore it’s B’s scrimmage line that football’s rules define as the point beyond which the passer cannot throw a legal pass. Can any part of the passer’s body be over B’s scrimmage line when the pass is thrown? Yes. It is the location of passer’s forward foot at the moment the pass is thrown that determines the legality of the pass. The passer’s entire body may may be lurching forward and across B’s line so long as his forward foot is still on his team’s side of B’s scrimmage line.

There’s more. In a more extended treatment of this topic I would turn now to discussion of (1) the expanded neutral zone (which extends the zone an additional two yards into the defense’s territory, and is important in both pass plays and punts), (2) the free blocking zone (which is defined around the line of scrimmage, and provides an area in which certain otherwise illegal blocks are temporarily permitted), and (3) the neutral zone as it is defined in relation to free kicks (or what are termed “kick-offs” in ordinary language). But enough has been described already to convey this essay’s central point.

Long before I donned an official’s uniform and nervously walked out on the field to work my first JV-level game, I used to watch “You Make The Call!” commercials on TV. Little did I then suspect that the expertise that a seasoned football official brings to his craft is not simply one of knowing the rules rather better than the average, or even the most devoted, football fan. Football’s rules are part and parcel of a wider architecture of precise and interlaced language. To administer the rules well and fairly a football official must achieve a seamless mastery of that architecture. To be sure, this specialized knowledge includes some surprising and entertaining esoterica. For the most part, though, it consists of deepened and enriched conceptions of such ordinary and humble ideas as the line of scrimmage.


(1) The referee (wears the white hat and is the crew’s chief official), umpire, head linesman (who manages the sideline “chain crew”), and the line judge.

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