As we discussed previously, there are rules about offense. You have to have 7 men at the line of scrimmage at the snap. Only the guys at the end of the line and in the backfield are able (eligible) to catch a pass. The guys "inside" must stand still for at least one second before the ball is snapped.
So, it makes sense to have the inside guys be offensive lineman - big burly guys - who can knock down the onrushing lineman. They don't have to be linemen in those positions, of course, but I have yet to see a team put anyone else in those positions.
The center is the guy in the middle. His job is to get the ball to the quarterback, and usually, he's the guy who watches what the defense does and tries to make calls so the offense adjusts to it. The people on either side of him are guards, because they are guarding the football (or more to the point, the quaterback). And the guys on the outside of them are the tackles. You may notice that on defense, the tackles are closer to the ball, but on offense, they're further away. I have no explanation for that one.
There's nearly always a quarterback on the field, and he can lineup "under center" which is a bit of a misnomer, because the only thing that's under the center are the hands of the quarterback; or he can go into the shotgun, where he stands back 2-3 yards behind the center. The shotgun is a way to slow down the defensive rush, and give the quarterback an extra second or two to look downfield and throw the ball. It almost always is used to pass.
The other 5 players vary depending on the situation. A "pro set" consists of a fullback, a half back, a tight end, and two wide receivers. But, you can go "full house" or "elephant" where you have three running backs who are fullback size (or an offensive lineman used as a blocker). You can also go to three wide receivers to give more passing options, or two tight ends to get more blockers.
Remember that the side on which the tight end lines up is the strong side, because there's an extra blocker on that side of the line.
The late Bill Walsh is widely credited with innovating on offense. He ran unexpected plays out of particular formations, had his quarterback running a bit, and used running backs extensively as ball catchers, rather than runners.
So, here's how a running play develops: the quarterback gets the ball, and will turn and hand it to the running back. There's an art to this, and often is based on reaching to a space, rather than actually seeing the player. The running back has the goal of running to a certain location along the offensive line. Many times, he'll be following the lead of the fullback, who runs to that spot first. After the runner gets past that spot, its up to him to make things happen. His breakaway speed or his ability to run over a player attempting to tackle him is up to his skill.
In general, the linemen in this case are typically pushing the guy in front of him out of the way. But, based on the scheme, they may be doing some odd things, such as "trap blocking" where one lineman stands up and moves, and someone else moves over to block the defender closest to the first guy. Or the guard stands up and runs to the other side to lead the runner. This is called a pulling guard.
On running plays, the lineman can go up the field, past the line to continue blocks.
The receivers need to "sell it" to the linebackers and defensive backs, so they think it might be a pass and are out of the play.
When its a passing play, the quarteback will take a few steps backward and look for an open player to throw the ball to.
The lineman this time can not go past the line of scrimmage, lest they be called for going out for a pass. Instead, they spread out into a horseshoe with the quarterback kind of in the middle. This is referred to as the "pocket" because it is shaped something like a pocket on a pair of pants.
Usually, the fullback will stay in to block, should someone get through. Everyone else has a route to run. That is, they should be doing something specific to try and evade the defense and be in a position to catch a pass.
They can leave extra players in to block if they need to, but that changes what the defense might do as well.
Offenses often try to figure out what defenses are doing. One way to do this is to put a man in motion. They can have the one person moving before the ball is snapped, as long as he doesn't turn to run up the field. Often, when you see this, the object is to find out if the defense is in "man to man" coverage or a zone. If a defender moves in step with the player in motion, you've got a man to man coverage happening.
Then again, some of it happens after the snap. A screen pass is one that goes a very short distance to a receiver or a running back. But, the trick is to allow the rush to get near the quarterback, and that way he can loft the ball just over the defenders, who won't have time to turn before the ball is caught. And, there are already blockers who are near the receiver.
A couple of tricks that the offense can throw out there are:
* The draw. This is a delayed run. The offense sets up to pass then the quarterback hands the ball off
* Play action. The quarterback pretends to hand the ball off, but actually keeps it and throws it down the field
* The flea flicker. The quarterback hands the ball off, and the runner starts up the field, but stops, turns around, and throws the ball back to the quarterback, who then throws it down the field.
* The statue of liberty (which rarely gets called) which is where the quarterback hands the ball off after they have set up to pass and has already looked for a receiver. Its an awkward looking play to say the least.
* A naked or against the flow run where everything appers to move one way and one person moves differently.
...and that's our lesson for today. Next time, we'll start getting into some detail.