Have you ever been watching a game and wondered why a team doesn't use a formation that you think would be great?  Why does a team send players in motion.  What about what a QB is looking at when he is under center?  What does audible mean, other than "able to be heard?"  Are there audibles that can't be heard?

In the spirit of Hoosierteacher's great recent work explaining defensive concepts and methodologies, I've decided to put some general football educational items down related to offense.  Please add your thoughts on anything I include or don't include, as I'd like this to be a value-adding discussion for all MHR readers.

Formation Rules and Constraints

Most people know that a full complement of players on the field at any one time consists of 11 players.  It is required that seven players occupy the offensive line of scrimmage at all times.  That leaves four players in the offensive backfield.  You can have more than 7 directly on the line, and less than 4, but only the two End men on the line of scrimmage are eligible to receive a forward pass, regardless of how many line up there.  Lining up inside the end man is called being covered.  In the case of this illustration, we'll call those two players the Split End (SE) and Tight End (TE.)

The 4 backs consist of a Quarterback (QB,) a Halfback (HB,) a Fullback (FB,) and a Flanker (FL.)  Note that the term Wide Receiver (WR) is used interchangeably for SEs and FLs, but Split End and Flanker are the more descriptive and technically correct terms. 

This is a pretty standard two running back personnel grouping I've described.  Each of these players is also eligible to receive a forward pass.  Different teams use different groups of players together, and our Broncos are especially known for changing their groupings up.  The key point to take from this is that there are always seven men on the line, and four men in the back field, and that the two end men on the line and the four men behind the line of scrimmage are the only players who are eligible to receive a forward pass.  This is the only real constraint to formation design.

Motion

Only one player lined up in the backfield may go in motion.  Such a player is permitted to take one step forward and then must move laterally parallell to the line of scrimmage.  If you ever see a bunch of players moving at once, that's not motion.  That's known as a shift, and those players are required to come to a set position for at least one second before the ball is snapped.  Only one man may be in motion at the snap of the ball.

There are three main reasons to send a player in motion.  The biggest historical reason is that it tips off the QB if the defense will play zone coverage or man-to-man.  If a specific defensive player follows the man in motion, that's a good hint that the coverage will be man-to-man.  Defensive coaches have gotten smart in disguising coverages, and you can't always tell from motion, but you can get an idea.  The second reason is to get a receiver a free release from the line of scrimmage with a lateral running start.  The third reason is to get a blocker a running start, particularly when a fullback or tight end lined up in the backfield is to isolate on an outside linebacker to lead an outside run.

A QB's Pre-snap Reads

I can't fully do this topic justice in terms of its complexity, because different coaches teach QBs to look at different things, but I can provide a flavor of what a typical QB is looking at before a snap.  The main focus is on the positioning and individual abilities of defensive personnel. 

The first question is, how many defenders are playing close to the line of scrimmage? ("in the box")  If the answer is seven men, the QB may consider changing a play to a run.  If the answer is eight or more, a pass sounds like a favorable matchup.  The key to this question is the positioning of the Strong Safety.

Next, the QB should ascertain the positioning of coverage personnel like Cornerbacks and Safeties.  Are the CBs far off the line?  Are they playing inside or outside coverage technique?  Are the safeties playing wide, or hugging the hashmarks?  Is there an opportunity to throw a deep ball against single coverage?  (Provided the down and distance is appropriate.) 

The third big question is, is there any indication of a blitz or an emphasis on a type of coverage (man-to-man or zone)?  This is huge, because it leads to changing of pass routes and also blocking schemes, sometimes.  Maybe the QB wants a TE to stay in and pick up the OLB he sees ready blitz.  Maybe he wants the FL to break off his route short because his CB looks like he's blitzing (this is called a hot route.)  As previously mentioned, motion can help tip the defense's plans.

The fourth major question becomes, is there a man-to-man matchup that a defender can't possibly handle?  Is a linebacker going to try to stick with Brandon Stokley downfield?  Is a little smurfy CB going to try to defend Tony Scheffler in the red zone?

The final point I'd teach is to determine if there is  an inherent formational weakness in a defense as it is lined up presnap.  If I have three fast WRs to the left, and the defense has its two CBs on either side of the field like they're just going to run cover-2, they're in trouble on the left side against all that speed.  The same goes if you have a bunch of tight ends to one side that you want to run to, and the defense doesn't line up accordingly.  All those TEs can clear the way for a long run to the under-staffed side of the field.

More calculations are being done than just these five listed above, but these are the main points of emphasis for a QB.  A really advanced QB like Peyton Manning almost always gets his team in the correct play for what they're about to face from a defense.

Audibles and Sight Adjustments

As I teased in the opening paragraph, an audible is verbal notification between a QB and other offensive players that a play is changed from what was called in the huddle.  Audibles can be elaborate, like you see from Peyton Manning, who essentially calls his own plays at the line of scrimmage for the Colts.  More often than not though, especially with younger QBs, an audible will be what's called a "check with me."  If a pass play is called in the huddle, often a running play that fits the personnel grouping on the field will also be called as a check with me.  The QB has the option at the line of scrimmage to keep the pass play that was called, or switch to the run play, based on the look he gets from the defense.  One phrase can also trigger the changing of the play ,if everybody knows what the check with me play was, and this cuts down on mixed signals.  This is essentially partial autonomy for the QB from the offensive coordinator.  Sometimes, you'll even see a QB even look to the sideline for a hand signal from a coach.

A sight adjustment is typically something that QBs and WRs do together, separately.  This is the case of a play changing with no words spoken.  The idea is that on pass plays, routes and releases of receivers should be adjusted based on the positioning of the Cornerback (CB) in coverage.  If the CB is playing far off the line of scrimmage, the sight adjustment will likely be to a WR screen.  If a CB is playing bump and run, and it looks like safety help is far away, the sight adjustment would be to go deep.  For inside coverage technique, the receiver would take an outside release, and vice versa for outside coverage technique.  Down and distance situations also come into play, somewhat.  That WR screen doesn't look so good on 3rd and 12.  The trick is, QBs and WRs need to be on the same page with this stuff, and that takes time playing together and trust.  This is the main reason that even the most talented rookie WRs tend to take awhile to get going as NFL players, as there is a significant mental component to what they're doing in the NFL.  Both QB and WR need to read the coverage, and they need to come to both the same read and the same adjustment.

I'll write about more of this kind of stuff as time goes on if this post is well-received and there seems to be interest in it.  As I mentioned before, please feel free to add to the discussion and challenge anything I have written tonight.  We'll all become better-informed Broncos fans together.