Unlike professional basketball or baseball, it's nearly impossible to put up big-time numbers over a long stretch of time in the NFL.
Some players are just due for a huge drop-off in production.
While some won't have success because they've taken too many hits over the years, other players will lose steam due to factors like age, circumstance and system.
Here are a number of those players who will severely drop off in 2012.
Michael Turner's down-hill running style is reminiscent of a different time in the NFL, which was characterized by hard-nosed offensive schemes and a more power-type game.
Unfortunately for the Falcons, his between-the-tackles running has only served to take a toll on this rusher.
I can't see this running back having too hot of a season in 2012, considering the Falcons lost offensive coordinator Mike Mularkey (who knew how to use the back) as well as the wear and tear on Turner's body.
The Chargers lost two key pieces in Mike Tolbert and Vincent Jackson this offseason, which can only serve to make Philip Rivers' task more stressful.
It's do-or-die time for Norv Turner, and I can't imagine that the Charger coach will put his job in the hands of his now-interception-prone quarterback.
Rivers will have to throw to a skeletal group of wideouts and an aging Antonio Gates, which doesn't seem like a recipe for success.
I could have put either of the Ravens' aging defenders (Ray Lewis or Ed Reed) on this list, but I chose to go with Lewis because of the physical toll that his body has taken over the last number of years.
Lewis won't have the luxury of playing with Cory Redding, Jarret Johnson and Terrell Suggs in 2012 which could kill his production and force him to make plays that he can't make anymore.
Look for this premier linebacker to finally succumb to age and circumstance in 2012.
No NFL quarterback takes more of a beating than Michael Vick does, considering the way that Vick plays and the dearth of penalties that this scrambler receives.
While he has all of the physical tools to succeed, all three of his division rivals beefed up their defenses in the offseason, and it will be tough for the Vick-led Eagles to make noise in a very crowded NFC.
Look for Philadelphia to lean heavily on running back LeSean McCoy when Vick starts slowly out of the gate; this may be the beginning of the end for the former Falcon signal-caller.
I firmly believe that the pre-draft buzz about the St. Louis Rams and Trent Richardson was more than just a smokescreen—the team knows something about Steven Jackson that we don't.
New coach Jeff Fisher has more success with running backs who can explode to the outside, and Jackson doesn't have that ability anymore.
I can't see it being much longer before the wheels fall off of this workhorse—this running back's time may be up.
Charles Woodson's been playing at a high level ever since he entered the league, but he's getting up there in age, and it seems as though his production is about to drop off.
The Packers have prepared for such, making sure to keep Tramon Williams and Sam Shields on the roster while drafting Casey Hayward at the cornerback position.
Woodson doesn't have the speed to match up with NFC North receivers like Calvin Johnson and Percy Harvin anymore, so a move to safety might be in everyone's best interests as this talented athlete plays out his final NFL years.
This may be the most subjective of my analyses on the slideshow, but I think Dwayne Bowe will drop off in 2012 simply because I saw something I've never seen from him before in 2011; Bowe quit.
I point to a Week 12 clash between the Steelers and the Chiefs in which, on one of the game's last plays, Chiefs' quarterback Tyler Palko threw the ball up to Bowe, and Bowe didn't even bother to jump for the ball.
The Steelers intercepted the ball and from that moment on, I doubted whether Bowe would have a good 2012 when everyone was back in place. The Broncos are a good team, and if the Chiefs fall behind in the standings early in the season, Bowe may quit again.