NFL fans hear the term "blue collar" incessantly. They hear about players who "bring their lunch pails to work" or "wear hard hats," from announcers, from writers and from NFL players themselves.

It is a frustrating term. Why? It seems to refer to a quality most normal people believe everyone should have—willingness to work. Put your head down, make a living and do your job.

But, NFL players can be divas just like everyone else can. NFL players can be drama queens or they can be ambition­less just like the next guy. "Blue collar" doesn't just mean a player makes less money than another. He might make less, but that's not the point. Being a blue­-collar player is simply a way of doing things.

It is a common phrase that the NFL "has a 100 percent injury rate" among its players. This weekend, for example, new Detroit Lions RB Reggie Bush told Vic Carucci and Dan Leberfeld on Sirius XM NFL Radio that he has not played completely healthy "since pee­wee football." Being a blue-collar player does not mean having the ability to play hurt. All NFL players must have the ability to play hurt, because they are always playing hurt.

If a player gets through a game relatively "unscathed," let's think about what that means.

For running backs, it's still brutal and just sounds painful. Popular Mechanics has measured some NFL collisions between linebackers and running backs to exceed 150 g's of force. Those are the big hits that feel like getting blindsided by a relatively slow­-moving bus. 100 g's or so is easier to imagine. That feels about like jumping off a 10­-foot diving board and landing on hard pavement with only football pads to shield you.

A hit at even 50 g's exerts the same force on a human body as an F-16 fighter jet roll. 

That's the life of an NFL running back on every play. A blue-collar running back can be the highest-­paid player on the team, and it doesn't matter. He will play through injury and take pride in small aspects of the game often overlooked by fans, such as pass protection and selling a great fake.

Blue-collar running backs practice. They set an example in practice, even as veterans who know the playbook in and out. During the season, it is important for running backs to be present and working at least by Wednesdays—just three days removed from the battering described above.

The reason is because Wednesday is when first- and second­-down install occurs for the week. Those are obviously primarily running downs, and having the actual personnel that will be taking part during game action helps immensely in practice.

A blue-collar running back doesn't think that taking "mental reps" from the sidelines on Wednesdays is an adequate way of doing things. He understands that having the entire unit in on drills helps everyone—especially younger players—in developing a natural level of comfort and familiarity with the personnel they will be surrounded by come game time.

A common theme in blue-collar players: Unselfishness.

In wide receivers, it is in willingness to sacrifice—not only their statistics, but their bodies. Blue-collar receivers are not afraid of crossing the middle and getting leveled on a dig route. They do not get alligator arms, and they pay strict attention to detail. In a position full of divas and trouble­makers, the blue-collar wide receiver puts his head down and executes his assignment.

A blue-collar receiver takes as much pride in blocking downfield for a teammate as he does in making a spectacular grab of his own. Typically, it is easy to identify smaller (or seemingly) less­ naturally gifted athletes as "blue-collar players" at the wide receiver position. Some guys look like natural athletic specimens, and some guys look like they work at it. 

For quarterbacks, a blue-collar presence has nothing to do with money. This is one example where the term "blue collar" fails to adequately do its job as a description. CEOs and corporate vice presidents can be "blue collar" in the same way that a quarterback can. Just because a player, executive or leader in any industry is operating outside of the blue-collar "tax bracket" financially, it does not mean their values cannot be solidly grounded within it.

Lots of millionaires in business grind 90-­hour workweeks.

A blue-collar quarterback is "one of the guys." Despite the paycheck and the interviews—the recognition and the endorsement deals—the blue-collar quarterback is no different than the rest of the team, which shares the common goal of winning football games.

A blue-collar quarterback is not a quarterback of the people or the fans, and cannot "craft" a blue-collar persona by partaking in blue­-collar activities such as getting drunk in bars or riding motorcycles. 

A quarterback is not "blue collar" just because he comes from a financially blue-­collar background or plays for a team that boasts a traditionally blue-­collar fanbase. A blue-­collar quarterback cares more about film and preparation than anything else, and would never throw a teammate or coach under the bus.

A blue-­collar quarterback does not care if the world knows that he is playing injured, and sets an example on the practice field. He will always gives teammates the credit for victories and great plays while taking all the blame for things that went wrong.

In linemen, it's motor. That's it. The offensive and defensive lines take a page out of the working man's book that simply reads "show up every day." Blue-collar linemen show up on every play.

They do not get sloppy in their stance when gassed, they do not skimp on their power step and they do not show any signs that their huge bodies are feeling any ill effects of the trench­warfare that takes place throughout NFL games.

For a lineman, being "blue collar" is being disciplined.

And that's really what we mean when we say "blue collar" in any walk of life. It indicates discipline, adherence to routines and hard work.