Almost every broadcast of an NFL game will make mention of a personnel grouping, usually by using a shorthand number scheme. The announcer may explain what that number means in that particular instance, but rarely is the numbering system explained. What are the rules? What the heck is “eleven” and “twenty-one” and how can I keep them straight?
Like many things in football, the answer is probably more simple than you might think, but with rules to keep in mind. A couple of important rules to keep in mind:
- Each team is allowed a maximum of 11 players on the field
- At least 7 players must be on the line of scrimmage at the snap
- Only 2 players, the outside player on each side, on the line of scrimmage are eligible receivers
To fit those rules, offenses employ five offensive linemen to block for the quarterback, the player who lines up to take the snap, and the other five offensive players. Those other five offensive players, commonly referred to as “skill positions,” fit into one of three main categories: running backs (RB), tight ends (TE), or wide receivers (WR).
A running back includes any player other than the quarterback who lines up between the tackles and behind the line of scrimmage, an area commonly referred to as the “backfield.” A tight end includes any player that lines up outside of the tackle but close in proximity to the offensive line. A wide receiver includes players that line up well outside of the offensive line to either side.
Based on the rules above, a team can use anywhere from 0-3 running backs, 0-5 tight ends, and 0-5 wide receivers. Note that in the visual below, a five tight end set (“05”) is not shown because it doesn’t have a practical usage in a real game but is theoretically possible.
The numbering system uses a two digit number with the first number representing the number of RBs and the second number representing the number of TEs. The number of WRs can be inferred by taking the number 5 and subtracting the number of RBs and TEs. Tip: The order of the numbers follow an alphabetical assignment with Running Backs before Tight Ends, with the last alphabetical position, Wide Receivers calculated last.
The visual shows a way to think about each personnel grouping on a grid, with the number of running backs (blue circles) increasing in each row and the number of tight ends (orange circles) increasing in each column. The wide receivers (red circles) make up the difference. An example formation is shown in each square with the NFL usage rates for 2021 shown in the lower right hand corner. Throughout the 100+ years of NFL history, personnel group usage has shifted plenty, but in 2021, the “11” personnel reigns supreme (59%) followed by “12” (22%) and “21” (7%).
Find me on Twitter @gridironborn.