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There are so many ways to break down how NFL teams build their roster. Some teams build with youth while others collect veteran players. While no one formula for stacking an NFL roster is iron-clad, one rule in the NFL is: Teams are only allowed to have 53 players on their active roster. Of these 53, only 46 players can dress out for the actual game.

Baseball has sabermetrics, but football coaches and front offices have had to deal with formulas for years. How to decide who to play week in and week out is a math problem in itself. Depending on who is injured in any one week plays a huge part in who is on the 53-man roster let alone the 46-man roster.

Each week in the NFL, you may see a transaction of a practice squad player (each team can have eight players on a practice squad each week) activated to the 46-man roster just for one game due to injuries at his particular position. Then on Tuesday, he is released from his contract in hopes that he clears waivers to go back to the practice squad. The behind-the-scenes action that takes place in a typical NFL franchise on a daily basis makes for great drama.

Having a simple understanding of how a 53-man roster is massaged each week will help you understand the offseason plan most teams use to build the roster heading into the season.

Each club is different and how many players are kept at each position depends on the type of offense and defense each team plays. If a club plays a 3-4 base defense, the team will keep more linebackers than defensive linemen. If a team does not have a strong-legged kicker, that club may keep two kickers on the roster. One player for field goals and the other to kick the football off.

A majority of these decisions are made in July and August before any real football is played. But every preseason, players rise to the forefront and make coaches and personnel change their minds. For this article, I will break down a team that uses a base offense and 4-3 base defense. I will also use the premise of one kicker, one punter and one long-snapper.

Quarterbacks (2)

The hot trend the past couple of years in the NFL is to only dress two quarterbacks on game day. With most teams employing a wide receiver or running back to serve as the emergency third quarterback, there is no reason to dress more than two quarterbacks.

Now this number could jump to three quarterbacks on the 53-man roster if the third quarterback is a young talent the team is trying to hide from other teams or develop.

Teams may also keep three quarterbacks on the roster if the first two quarterbacks are injured or injury-prone.

Running backs (4)

With the NFL becoming a passing league, most teams still keep four backs on the 53-man roster due to injury history at the position. Most NFL teams employ a backfield by committee approach and most teams include a fullback in this number.

Special teams play a huge role in this number as well. Most running backs have speed and can be a force on special teams.

One of the best in the NFL is Jacksonville Jaguars running back Montell Owens. Though he is listed as a fullback now that Greg Jones has departed, Owens was seen as a special teams demon and Pro Bowl player. This increases his value and keeps him active on game day.

If a team like Jacksonville dresses a fullback for the game, it will probably dress three other running backs as well. The starter, the primary backup and a special teams player should all dress on game day.

Wide Receivers (6)

Most teams will keep six wide receivers on the active roster but will only dress five for the game unless the sixth player is a warrior on special teams. This allows the coaching staff to line up in four-wide formations without losing speed or talent.

Normally the top four wideouts will not play on special teams unless they are a returner like Baltimore’s Jacoby Jones. Rarely is one of the team’s top three wide receivers also the primary returner. That role is typically held by the fourth wide receiver or another position.

The sixth wide receiver on the roster will normally be inactive on game day and is either a talent the team wants to work with in the future or a high draft selection that needs work at the NFL level. Think of San Francisco wide receiver A.J. Jenkins.

Tight Ends (3)

Unless you are the Green Bay Packers, who at one point had five tight ends on the 53-man roster in 2011, most teams will keep three active tight ends. The typical breakdown is the starter, who is a threat in all phases of the game. The backup is usually a blocking tight end who is not much of a threat in the passing game. The third tight end is a hybrid type who can also help on special teams.

Almost always are all three players active on game day, and both the backup and third tight end will be expected to contribute on special teams. Some teams will keep four tight ends active if they do not incorporate a full back in their offense. Most NFL teams will keep a tight end on the practice squad to activate for game day in case of injury.

Offensive linemen (9)

This is the position that causes coaches and personnel men to lie awake at night. Most teams would love to keep 10 offensive linemen on the active roster because they are so hard to find on the street. Coaches and personnel will fight over how many offensive linemen to dress on game day. Can the backup offensive guard play center if called upon? Can the starting right tackle kick over and play left tackle in case of injury in the game?

Having versatile linemen on the roster is the key for successful teams. If a club can get away with dressing only seven offensive linemen like the Pittsburgh Steelers did at times in 2012, that allows the team to dress more players at other positions. Even if a team dresses eight players for game day, most personnel men would love to have a total of 10 players on the active 53-man roster due to the lack of depth at the position league-wide. Every general manager wants to have two developmental types for the coming years on the roster.

Offensive side of the football: (24 total players on 53-man roster, game-day roster 2 QBs, 4 RBs, 7 OLs, 3 TEs, 5 WRs = 21)

Defensive linemen (9)

Again, I am writing this as if I am the general manager of a 4-3 base defense team.

This would be seven or eight players if the base front was a 3-4. Most teams will keep a two-deep roster on the defensive front with a young developmental player in the ninth spot. Some teams will keep a “designated pass-rusher” on the roster and will dress them on game day. Most NFL teams dress eight players for the game. Again, this can change based on injury.

Some NFL teams may keep six defensive ends and only three defensive tackles if they have a versatile backup. Also, with so much passing taking place in the NFL, some teams will use defensive ends as interior pass-rushers in obvious passing downs. This eliminates the need for an extra run-stopping defensive tackle.

Linebacker (7)

The core of an NFL team’s special teams unit comes from this position. Most teams will only play three linebackers in a game, and with the explosion of the NFL passing attacks, the strong-side linebacker is rarely used on passing downs. Most teams use the fourth linebacker as the “nickel” linebacker in passing situations.

Some teams employ a hybrid safety/linebacker in passing situations to counter teams like the New England Patriots’ tight ends and players of their ilk. Unless the linebacker is a dominant force like San Francisco linebacker Patrick Willis or Kansas City Chiefs' Derrick Johnson, even starting linebackers will be asked to play on special teams coverage units. That is why most NFL teams will keep and dress seven linebackers.

Defensive backs (10)

Most teams will only dress eight on game day but may dress nine defensive backs if they only activate six linebackers for the game. Most NFL teams will build their roster with four starting-type cornerbacks. Almost every week, all four will be activated for the game. Add in the starting safeties and that leaves four total roster spots. Depending on the type of defense that is being employed, some general managers may keep three cornerbacks on the roster and one extra safety.

If the team likes to use a safety closer to the line of scrimmage, four total safeties will be kept on the team. The fourth and fifth cornerbacks better be great jammers and gunners on the punt and punt return teams. The backup safeties will be staples on all the coverage units. Most teams want to ease young safeties into action, but they can get a feel for the speed of the NFL by being warriors on special teams.

Defensive side of the football: (26 total players on 53-man roster, game-day roster 8 DLs, 7 LBs, 7 DBs = 22)

Add in the one kicker, the punter and the long-snapper and the 53-man roster is built.

There are so many variables that go into this equation but this is a solid example of what coaches and front-office personnel do all year round. They are continually tweaking the roster not only for salary cap issues but for quality depth and ability of all the players.

Marc Lillibridge is a former NFL linebacker who scouted for six years in the NFL following his retirement. He is now a certified NFLPA contract advisor for www.profootballsyndicate.com.