Which NFL Running Back's Wheels Will Fall Off in 2011?

Great running backs are a joy to watch in action, but there comes a time in every great running back's career where he seems to lose that half-step that made him so great, and the rest of the league catches up to him.  It happens to at least one back every year, but the difficult part is identifying who that will be BEFORE it happens.

Let's look at a few former stud backs to illustrate this concept:

• LaDainian Tomlinson 
• Ran for over 1200 yards in each of his first seven seasons in the NFL, all with the Chargers. 
• Had record-breaking year in 2006 with 1,815 yards and 28 TDs. 
• After that year, in 2007 had 1,474 yards and 15 TDs (still a great year), but in 2008 that dropped to 1,110 yards and 11 TDs and he hasn't come close to those numbers since.
• Had 2,657 rushing attempts before 2009
• Tomlinson is unusual in that he ran for so many yards for so many seasons in a row. That is unusual, and occurs only a couple of times in any running back generation.  It's difficult to know which running back is going to have that longevity when they're younger.
• Larry Johnson 
• Had two MONSTER years in 2005 and 2006 where he ran for over 1700 yards and over 17 TDs each year.  
• Johnson held himself out of training camp before the 2007 season, wanting a new contract. He received the largest contract in Chiefs' history and promptly never ran for more than 900 yards in a season afterwards.  
• Illustrates the danger of two things: Holding out of training camp, and getting that new monster contract.  
• Had only 892 rushing attempts before wheels fell off, but his last great season he carried the ball an insane 416 times. Was that what did it?
• Shaun Alexander  
• Had five excellent seasons for the Seahawks, culminating in 2005 when he ran for 1880 yards and 27 touchdowns.  
• Promptly signed a new contract before the 2006 season, and never ran for more than 900 yards in a season afterwards. In fact, his career ended in the 2008 season. Injuries played a large part in that.
• His major issues then were new contract and injuries.
• Had 1,717 rushing attempts before the wheels fell off in 2006.

So now, after looking at some former running back studs who had monster season, let's look at some running backs still seemingly in the prime of their career and figure out which one will fall off first:

Adrian Peterson

• Adrian Peterson 
• About to start his fifth year in the league, and the first four saw him gain an average of 1,445 yards and 13 TDs/season. 
• Will have more pressure on him this year now that Brett Favre is gone.  Meaning, he should get more touches and be a bigger factor in the offense, which is both good and bad.
• Had accumulated 1,198 rushing attempts in the regular season in his career.
• Entering the final year of his contract, but is not holding out of camp as a result. He seems motivated and focused on this new year, with better opportunities than what he's had the past two years.

Chris Johnson

• Chris Johnson 
• Has played three years in the NFL, averaging 1,532 yards and 11 TDs each season.
• Currently holding out of training camp in a contract dispute. If he gets a monster contract, how will that affect him?
• Has 925 rushing attempts over his first three years, which is a slightly higher pace than Peterson's.
• Is three inches shorter and 20 lbs lighter than Peterson. Can he hold up?
• Also going through a head coach/quarterback change.
• Jamaal Charles
• Has three years in the NFL, with two really good years in 2009 and 2010.  In those two seasons he's averaged 1293 yards, but only 6 TDs each year.
• Some consider him a fantasy riser, but the concern lies in his touchdown production.  The Chiefs are an up-and-coming team and should continue to get better on offense. However, in Head Coach's Todd Haley last position as offensive coordinator in Arizona, the running game was not emphasized.

Ray Rice

• Ray Rice
• Just like Charles, has two really good years in 2009 and 2010 where he averaged 1279 yards and 6 TDs.
• Same concern as in touchdown production, but was sharing carries with short-yardage specialists like Willis McGahee who scored 12 touchdowns himself the past two years combined.  He is now gone to Denver, and Rice should be the featured back in this offense.
• Maurice Jones-Drew
• Has played five seasons in the NFL, averaging 1,049 yards and 11 TDs.
• Past two years averaged 1,357 yards and 10 TDs despite missing two games at the end of the 2010 season.
• The injury was a torn meniscus in his knee, which raises concerns about his future injury probability
• Has 1,141 rushing attempts in his career, which is a much slower rate than either Peterson or Chris Johnson (but has averaged 305 past two years)
• Size is a concern, as he's only 5-8" and 208 lbs.

So in looking at these top running backs, the most likely players to have their wheels fall off in the next season are Maurice Jones-Drew (size/injury concerns), Jamaal Charles (system he's in, lack of touchdown production means he's not a focus of offense), and Chris Johnson (holding out/about to get monster contract).

I'm probably wrong on Chris Johnson. Feel free to tell me in the comments.