Over the course of NFL history, the game has changed and progressed throughout the decades to become what it is today.
But no single position has changed more in the last 20 years than the running back.
Once the single most important position on the field, running backs are now seemingly being phased out of the game. Gone are the days of Jim Brown, Eric Dickerson and even Barry Sanders as we welcome in the new era of running back by committee.
And that system makes sense for today's NFL.
The game today is built around the quarterback and the passing game. In 2011, we saw two QB's break a more than 25-year-old passing record set by Dan Marino in 1984. There were three quarterbacks with over 5,000 yards passing and 10 over 4,000.
One would think, with the giant passing numbers being put up, that the running game was dying in the NFL. But that simply isn't true.
It's evolved. And what it's evolved into is the running back by committee system.
Take the New Orleans Saints, for instance. In 2010, the Saints had just two players carry the ball more than 70 times and their running backs ran for just over 1,400 yards. It's a respectable number, but a lot of single backs can manage that over the course of 16 games.
In 2011, however, four Saints running backs carried more than 70 times and their rushing total skyrocketed to over 2,013 yards, averaging over 125 yards per game. New Orleans won 13 games in 2011 and ranked sixth in the league.
There are still some teams who employ single-back systems. Adrian Peterson is the clear-cut guy in Minnesota and Ray Rice is the Ravens star. But more and more, one-back teams are being phased out of the NFL. Even the Texans like to throw Ben Tate more carries than you'd expect.
One interesting case to look at this year is going to be the San Diego Chargers.
In 2011, the Chargers employed a committee system between Ryan Mathews and goal-line pounder Mike Tolbert. The two combined for 1,582 yards on the ground, another 888 through the air and 16 total touchdowns.
But after letting Tolbert walk in free agency, San Diego is putting all their eggs in Mathews' basket. The team signed Ronnie Brown, but he's not going to contribute what Tolbert brought to the team.
It will be very interesting to see if the Chargers can have success with just Mathews or if they'll miss Tolbert at all.
Having a running back by committee system makes sense in the NFL today because it gives you as many options as needed for a coach. Instead of having one do-it-all back who can wear down quickly, why not have one guy who can catch, a guy for the goal line and another to be the feature back?
As 2012 progresses, it'll become more clear that the NFL has made the move to this new running back system. Who knows if we'll ever see the kind of backs who used to bowl over defenders in the 70s and 80s; and who knows if we'll ever need to.