The Playbook Confidential series takes a left-brained look at the Chargers offense and how to predict it. We try to correlate the situation (down, distance, game clock) and pre-snap information (personnel, formation) with post-snap outcomes (run/pass mostly). Throughout the season, BFTB will keep a detailed log of every Chargers offensive play, updated every week and publicly available on a Google docs. The pre-season opener vs Green Bay presented very little of interest for those familiar with Norv's offense, so we're just going to bring everyone up to speed this week.
At BFTB we use a simple and fairly standard two digit annotation for the offensive personnel on the field for any given play. Aside from the quarterback and offensive line, there are 5 skill players left to fill out the huddle. Those skill players come from running backs, tight ends and wide receivers. We identify the skill players with one digit for the number of running backs, the second digit for the number of tight ends, where the number of wide receivers is the balance of the 5 skill spots. 21 and 12 form the backbone of Norv's offense.
|Personnel||What it means||Notes|
|11||1 RB, 1 TE (3WR)||Think of 11 as 3 WR|
|12||1 RB, 2 TE (2 WR)||Usually Gates as a slot and McMichael blocking|
|21||2 RB, 1 TE (2 WR)||2 RB means a Fullback is in the game|
|22||2 RB, 2 TE (1 WR)||This is for not hiding the intent to run|
|23||2 RB, 3 TE (0 WR)||This is for super jumbo run|
BFTB staffer jkvandal introduced us to this personnel annotation in this story. He points out that Norv likes to use the first few possessions of any given game to sample opposing defensive reactions to various groupings. The key here is that the defensive coordinator and on-field captains have a good 20 seconds to react to the personnel group in the huddle, while the formation isn't shown to the defense until much closer to the snap.
We're going to add in formation tracking this season. There are a million different formation terminologies and a million variations on every formation. We're going to try to find something relatively simple. While our personnel grouping tells us a lot about the backs (two running backs will almost always mean a fullback in I formation), we'll use formation tracking to tell us more about what the WR are doing. Personnel tracking pays close attention the difference between tight ends and wide receivers; formation tracking will pay attention to how the pass catchers as a group are lining up (we won't care if it's Eddie Royal or Antonio Gates in the slot). Motion can change the offensive formation, but whatever formation they end up in is the true formation they are running from.
|Backfield||Combined w/ WR||Explanation|
|Single Back||Ace||Single Back with one receiver on each side|
|Single Back||Ace Double||Single Back with two receivers to one side|
|Single Back||Ace Spread||Single Back with two receivers on one side and a third on the other|
|I Formation||I||Running back and Fullback with one receiver on each side|
|I Formation||I Double||Running back and Fullback with two receivers to one side|
|I Formation||I Spread||Running back and Fullback with two receivers on one side and a third on the other|
|Shotgun||Shotgun Spread||Shotgun with two receivers on one side and a third on the other|
||Shotgun with two receivers on one side|
|Shotgun||Shotgun Trips||Shotgun with three receivers on one side|
|Shotgun||Shotgun 2x2||Shotgun with two receivers on each side|
Lessons from 2011
Here is the play calling log from the entire 2011 season. Every Chargers snap is in there. Norv Turner's offense is execution based. He doesn't intend to mislead you; he intends to impose his will on you. The offense runs 40% of the time, with 12 and 21 personnel as the staples on 1st and 2nd down. On 3rd down and anything other than 1-2 yards to go, you'll see shotgun pass from 11 most of the time. A 3rd and one is a fullback dive every time. Last season, Turner used Mike Tolbert over Ryan Mathews in any situation involving third down, two minute drill, or goal line. I have a hunch that Turner will use Ronnie Brown in that exact same role. Because Norv favors execution over trickery, he doesn't care that Mathews in the backfield on 1st and 2nd down is a huge run-tell. There are a couple of summary posts I did here (at the bye) and here (at the end of the season). Reader dts317 did some really great analysis at the end of the season using a success rate system. It turns out 11 is the team's best personnel group.
About That Green Bay Game.
Here is a sample of the 2012 play log using the 4 Rivers possessions of the Green Bay pre-season game. It's better organized to show what parts are the situation, the pre-snap shows, and the outcome.
|Week||The week the game took place|
|W/L||Whether San Diego won or lost the game|
|GTG||If the down and distance is "Goal to Go"|
|Lead||L for San Diego Leading, T for Tie, B for Behind|
|Posession||Possession number for the game|
|Ball On||Keeps going up in opposing territory from 50-99 yards|
|RunningBack||The halfback in the game on this play|
|Heavy||If there are tight ends next to the oline, which side is heavy|
|Call||P for Pass, R for Run Right, M for Run Middle, L for Run Left|
|Playfake||Y if there was a play fake (Norv/Rivers do very little of this)|
|Carrier||If someone caught or carried a ball, who got it|
|1st?||If the play resulted in a 1st Down|
|Event||Something like a turnover or a sack|
|TD?||If the play resulted in a Touchdown|