You can't predict the future, but you can get a sense of it.
Looking at how an offense lines up—which players are on the field and where they are in the formation—provides clues that give defenses and viewers a sense of what's to come.
Suddenly, a game that seems complicated to casual viewers becomes a lot easier to watch.
It all starts with identifying the players on the field.
The different offensive personnel groupings have different names. If you say "four-wide receiver set," you have some of the information, but there's a system that takes us deeper. In fact, there are standardized ways to name the offensive personnel groupings.
Here's how it works: Barring nontraditional formations, an offense lines up with five linemen and a quarterback. That leaves five "available" spots on any given play, and those spots will be manned by running backs, tight ends and wide receivers.
Each personnel grouping is named with two numbers. The first number is the number of running backs, and the second is the number of tight ends.
So, for example, if a team sends out one running back and two tight ends, it's called 12 personnel. If a team sends out two running backs and one tight end, it's called 21 personnel. Those groupings will each feature two wide receivers, since three of the available spots are taken. The 11 personnel is one running back, one tight end and three wide receivers, and so on.
Some teams do it differently (Matt Bowen of National Football Post indicates there's a system in which the groupings are identified using a deck of cards with words like Ace, Kings, Queens etc.), and different coaching staffs have their preferences, but the numeric system is the simplest to understand and quickly recognize, from this perspective.
A personnel grouping can indicate whether a team will run or throw the ball. Of course, the 22 personnel (two backs, two tight ends) hints strongly toward a running play, while the 10 personnel (one back, four receivers) is a spread set that looks like a passing play.
Defenses can respond to these sets by matching personnel. For example, a defense might field extra linemen or linebackers against the 22, whereas they might go to the nickel or dime package with extra defensive backs against a spread formation like the 10.
In the chess game that is football, the personnel groupings can provide a clue as to what the opponent's next move will be, or they can be used as a decoy of what's to come—fake the jab, hit 'em with the uppercut.
Now that we understand the basics of what we're looking at and why we're looking at it, let's take a look at all the different groupings, their strengths and weaknesses, and examples of some of these groupings in action.
00, 01, 02
Spread 'em out.
With five linemen, five wide receivers, one quarterback and no running back, the offense is telling the defense one thing: We want to throw the ball.
Usually, this package is saved for 3rd-and-long, late-game catch-up situations, or a Hail Mary.
Teams that employ spread formations like this will need to be deep at both receiver and tight end, with a versatile group of players that can hurt a defense in a number of ways.
Tight ends can line up wide in these formations to run a route, or they can be used as an in-line blocker in protection to chip a pass-rusher before he engages the offensive tackle. Though this is not necessarily the case, more tight ends on the field could mean longer developing routes down the field as an offense employs extra blockers to buy the quarterback more time in the pocket.
In the season opener against the San Francisco 49ers, the Green Bay Packers at one point used the 01 personnel grouping in an interesting way. They came out with four receivers (circled in red) and one tight end (circled in yellow). The defense responded with the dime package of three linemen, two linebackers and six defensive backs.
Wide receiver Randall Cobb lined up next to quarterback Aaron Rodgers in the shotgun. Cobb motioned out to the slot before the snap.
The play was designed to draw the defense into the backfield, with the passing formation indicating no threat of the run. With the defense bearing down on him, Rodgers threw the pass short to Cobb (circled in red) near the line of scrimmage. When the receiver caught the pass, tight end Jermichael Finley (circled in yellow) was already in front of him as a blocker. It was essentially a delayed run out of a passing set.
The play resulted in a 16-yard gain.
Although a team with a good running quarterback might occasionally use a spread set as a decoy for a designed quarterback sneak, lumping these all into one category is a way of saying there's little else to do with no backs in the backfield besides throw the ball.
With four receivers on the field, the threat of the pass is much greater than the threat of the run.
As we've learned already, though, a personnel grouping can be used as a sort of decoy to catch the defense off guard with a running play.
On 3rd-and-1 against the Tennessee Titans back in 2009, the New England Patriots came out in their 10 personnel with running back Kevin Faulk lined up behind quarterback Tom Brady. The Titans responded with the dime package of four defensive linemen, one linebacker and six defensive backs.
With the Titans geared up to stop the pass, Brady checked to a run. Five offensive linemen blocked four defensive linemen and a linebacker, and the secondary was too far away to make a play. Faulk easily picked up the Patriots first down.
In passing situations, the 10 personnel can be great to keep an extra blocker in the backfield with the running back, while still having plenty of options in the passing game.
The Packers often went with four receivers on the field and used the 10 personnel in this play against the Lions with running back Alex Green (circled in green) the lone back in the backfield.
The Lions responded with the dime defense: six defensive backs, one linebacker and four down linemen.
The defensive line was able to get pressure on quarterback Aaron Rodgers, but he used his legs to escape and extend the play.
That bought him enough time to see Donald Driver settle down in a soft spot in the Lions secondary, and the Packers completed the pass for the first down.
In going spread, an offense is trying to create matchup problems in the secondary and spread them out to create space in the passing game. Those receivers, as mentioned above, have to be quick enough to create separation against man coverage and smart enough to know the soft spots in the defense against zone coverage.
According to Football Outsiders, 11 is the most common offensive personnel grouping for 29 of the 32 teams.
With what we know about formations, it should come as no surprise. With three receivers on the field, the offense is in a passing formation. They have more speed and quickness on the field, as well.
This explains the advent of nickel defenses, as teams employ a fifth defensive back to account for the third receiver on the field. This has raised the value of having a deep secondary almost to the point where the fifth defensive back is a starter.
From there, the alignment of players can be a big indicator as to whether it will be a run or pass. If the back is lined up behind the quarterback, as in the diagram above, there's at least the chance this could be a running play—be it to the strong side (behind the tight end) or the weak side.
The shotgun formation, as we see from the Carolina Panthers in the diagram above, gives off more of a passing look. There are three receivers (circled in red), one tight end (yellow) to the right of the offensive line, and one back (green) lined up flanking quarterback Cam Newton to the left.
The Atlanta Falcons responded to this apparent passing formation with their nickel package of four defensive linemen, two linebackers and five defensive backs.
The Panthers run the option out of this set, which takes advantage of both running threats in Newton and running back DeAngelo Williams.
The Panthers were able to take advantage of the Falcons going small against the run, and Williams picked up an easy 10 yards.
Sometimes, even when you think you have an advantage, you really don't. Creating mismatches is a big part of what football is all about.
The 12 personnel grouping has become a favorite around the league. The Patriots popularized the set with their use of tight ends Aaron Hernandez and Rob Gronkowski.
Although they'll have to rethink their own approach to that personnel grouping in light of Hernandez's murder trial, they made enough of an impact over the past three years to greatly influence how other teams utilize and defend against 12 personnel.
Generally, in the 12, one tight end is more of a pass-catcher and the other has a bit better blocking ability. The presence of the pass-catching tight end helps create those ever-important mismatches, where a base defensive alignment will be vulnerable to the pass, while a nickel or dime package will be weak against the run.
The Patriots didn't have Hernandez and Gronkowski on the field together all that often in 2012; in fact, they were only healthy and on the field together in four games during the regular season. One of those games, of course, was in Week 1 against the Titans.
On 3rd-and-4 from the Titans' 10-yard line, the Patriots came out in the 12 personnel grouping with Hernandez lined up in the slot. The Titans matched up with the nickel defense, putting a cornerback on Hernandez. This was a decided advantage for New England; while Hernandez wasn't regarded as a great blocker, he was certainly more formidable at blocking than your average wide receiver.
Patriots running back Stevan Ridley took the ball off left guard and went eight yards down to the Titans' 2-yard line.
This was once regarded as more of a running formation, but teams can find balance out of the 12 personnel. According to NFL GSIS (subscription required), teams passed the ball out of the 12 on 1st-and-10 47.8 percent of the time, which is almost exactly the percentage of passing plays overall on 1st-and-10 (47.9 percent).
This is as close as a team can get to giving away its plans to run the ball while still maintaining some threat of the pass.
The 49ers were one of the most run-happy teams in the NFL last year, so it's no surprise they found plenty of use for the 13 personnel.
On 2nd-and-3 against the Arizona Cardinals, the 49ers lined up with one back (circled in green), three tight ends (yellow) and one wide receiver (red). Arizona responded by putting eight men in the box and two more inching closer to the line as the snap drew nearer.
49ers quarterback Colin Kaepernick turned and handed off to running back Frank Gore, who put his great footwork on display and picked up a first down despite a poorly blocked play.
Make no mistake—the 13 personnel can be used as a decoy as well.
In fact, the 49ers caught the Seahawks off guard in just that way in their Week 7 matchup. The Seahawks answered the apparent run personnel by putting eight men in the box, with cornerback Richard Sherman locked up alone on wide receiver Randy Moss on the outside.
The play is misdirection at its finest by San Francisco. They faked the run to the left and had quarterback Alex Smith roll to his right.
The defense drifted in the wrong direction initially, biting slightly on the play action. That was enough to buy Smith time to roll to his right, and with a wider window to make the read, he delivered a jump ball for Moss, who had already created separation on his route.
Just another reminder that offensive personnel can be a good indicator of what's to come, but it can also be a tool to catch the defense off guard.
The 20 is interesting because it's not one we see a lot, but it's incredibly versatile. The offense could line up in an I formation, with the quarterback under center and the two backs stacked behind him, as shown above, or it could be in the shotgun with the two backs flanking the quarterback on either side.
In an effort to get the ball into the hands of running back Doug Martin in a favorable matchup, the Tampa Bay Buccaneers opened the game against the Dallas Cowboys with 20 personnel.
The Cowboys responded with their nickel defensive package of four down linemen, two linebackers and five defensive backs.
Buccaneers quarterback Josh Freeman took the shotgun snap and made the delayed handoff to Martin.
The hope was that running back DJ Ware would clear the path, but the run went for just two yards.
While this is not a successful example of a running play out of 20 personnel, it does help shed some light on how teams can run the ball out of what looks like a passing formation.
Of course, that same formation could be used on a passing play, with the backs either running passing patterns out of the backfield or serving as blockers in max protection.
A formation featuring two running backs and two receivers can either be a great heavy running set with a fullback and a running back in an I formation, or could be a variation on the shotgun formation shown above. In either case, the offense can maintain a strong threat of the run without ceding the threat of the pass.
He picked up 65 yards and a touchdown on this run against the Raiders, with fullback Jorvorskie Lane in front of him and the offensive line power blocking to the left.
With Lane out in front of him, Bush got to the sideline and put his acceleration on display as he ran all the way to the end zone.
The play immediately prior to this touchdown run, however, the Dolphins proved they can throw the ball from this formation as well.
In practically the same formation, Dolphins quarterback Ryan Tannehill faked the handoff to Bush.
The defense didn't bite on the play action, instead charging hard at Tannehill. With multiple defenders bearing down on him, he made the throw outside the numbers to wide receiver Brian Hartline.
Hartline was able to get inside leverage against the cornerback to make the catch for a first down.
It was through the 21 personnel that Tannehill proved he can throw the ball well outside the numbers, as that is where the receivers will be lined up by default.
With one or no receivers on the field, these packages are generally for short-yardage and goal-line situations.
With the 22, there is at least some semblance of the threat of the pass, with a receiver split out wide.
The 23, however, is aptly named the "jumbo package" because it gets as many big bodies on the field as possible to drive those last few inches. In fact, some teams use an offensive linemen as the third tight end in order to create an even heavier jumbo package.
The offense could call a play-action pass from this formation to catch the defense off guard, especially if one of the tight ends on the field is an adequate receiver, but for the most part, this is a running set.
The Cardinals came out with 23 personnel on 2nd-and-goal from the 1-yard line against the Packers.
The Packers responded to the formation by bunching up everyone close to the line of scrimmage, with six down linemen, three linebackers and two defensive backs.
The Packers were able to seal off the middle, but Cardinals running back LaRod Stephens-Howling bounced the run to the outside and put his balance and quickness on display. He slipped through a tackle and made his way to the pylon for the touchdown in winning a footrace with the linebacker.
In fact, as teams get closer to the goal line, the percentage of rushing touchdowns increases drastically.
Conclusions and Further Learning
The offensive personnel grouping gives the defense a clue as to how they should match up and gives the viewer a clue as to what might be coming next. That being said, the possibilities are almost endless with each personnel grouping.
One thing to keep in mind is that personnel can often be dictated by the situation. A team that's ahead on the scoreboard might employ more running sets to try to milk the clock, while a team that's playing from behind might field extra receivers as it throws the ball to play catch-up.
Try watching the game through the lens of the offensive personnel.
Identify what grouping the offense is fielding on each given play by counting the number of backs, then tight ends, then either counting the receivers or subtracting the total of tight ends and running backs from five to get the number of receivers.
You'll then start to have a better idea of what's coming.
Erik Frenz is also a Patriots/AFC East writer for Boston.com. Unless otherwise noted, all stats obtained from the Sports-Reference.com network, and all quotes obtained firsthand or via team press releases.