Running back is a fickle position.
The window for success is short, leaving them about four to five years to be on top of their game.
With the passing of the guard always taking place at the position, there are numerous players primed for breakout seasons each year.
Last year, it was backs like Ray Rice, Cedric Benson, and Jamaal Charles who unexpectedly busted on the scene as top rushers.
So who's on deck this season?
Whether it's a rookie getting the look right away or a young back finally receiving his chance, there will be plenty of breakout backs this season.
Here's the list of the ten most likely candidates.
When Cedric Benson was sidelines with a hip injury last season, Scott smoothly took his place.
Although the performances might have been against soft defenses like Oakland and Cleveland, Scott showed off his shiftiness and speed and proved he's a valuable backup to Benson.
If Benson misses time this season, whether it's for suspension after a barroom altercation or from injury, Scott will get another chance to show what he can do.
Benson was noticeably slowed last season, so Cincinnati would be wise to take some heat off by dishing to Scott more.
If that happens, the elusive back could garner 500 to 600 yards behind a Bengals offensive line that thrives on run blocking.
It appears Julius Jones will come into training camp as the favorite at running back, but it'd be smart of Pete Carroll to insert Forsett into the starting spot this season.
Jones doesn't have the same burst he had in Dallas and is starting to fade quickly now that he's 28.
Both put up similar numbers, but Forsett was a much better threat for the Seahawks. The numbers don't lie. Jones only averaged 3.7 yards a carry, while Forsett garnered 5.4 yards a touch.
With Jones losing a step and Forsett only getting better, this can be the California alum's chance. If he established himself as the number one guy, a 1,000 yard season isn't out of the question.
It's tough for any running back to gain a lot of exposure in Indianapolis' wide open offense.
Joseph Addai has had some success, however, rushing for over 1,000 yards in 2006 and 2007.
It might be time for Addai to pass the torch on to Brown this season though.
Addai is slowing down and doesn't possess the same breakaway speed Brown shows in the open field.
Brown struggled with injuries and adjustments to the pro game, but he'll be healthy and more experienced this season.
It appears they'll split carries at the beginning of the year, but Brown could pull ahead early in the season.
Jerome Harrison busted on the scene late last season, but he'll have some stiff competition in the backfield with Hardesty.
The bruising second-rounder from Tennessee fits the power running style offensive coordinator Brian Drodell wants in Cleveland. While Harrison is phenomenal in space, he isn't the power runner Hardesty is.
Cleveland has a very underrated offensive line. Alex Mack has progressed into a top NFL center, and Joe Thomas and Eric Steinbach have always been elite. They'll make huge holes for whoever is at running back.
And with the Browns passing attack looking dismal, expect a lot of run plays. If that's the case, Hardesty will see an abundance of runs up the middle.
Both Harrison and Hardesty could thrive this year. With the move towards a power offense, it looks like Hardesty has the better chance.
McCoy was Brian Westbrook's backup at the beginning of last season, but when the veteran couldn't play due to concussions, he was thrust into the starting spot.
McCoy wasn't overly impressive in his rookie campaign and only rushed for 637 yards on the year. He also looked worn down by the end of the season.
Things should change this season, however. A new era has dawned in Philadelphia and McCoy is a big part of that. The second-year player focused on building endurance and has a valuable year of experience under his belt.
Now is his chance to succeed. The Eagles' offense has always featured passes to the running back and McCoy will see plenty of throws his way.
As the new man in Philly, McCoy will ascend in 2010.
Detroit is very intrigued with their second-round selection, and it should be.
Best offers the game-breaking speed that makes him a supremely effective runner in the open field. Despite injury troubles at Cal, he was dazzling when healthy.
Kevin Smith is recovering from a torn ACL and also had a disappointing sophomore slump before suffering the injury. After coming on strong as a rookie, he finished with 747 rushing yards last season.
Part of that can be blamed on a terrible offensive line, but with Best's ability to make things happen in space, he could accomplish more with the lack of blocking.
As one of the fastest players in the draft, expect Best to be one of the first rookies to make an impact in 2010.
Many expected Wells to burst onto the scene last season, but he tip-toed his way towards success in his rookie year.
The biggest knock on the running back is his hesitation as he hits the hole. He should shake those jitters this season.
The Cardinals have a new look after Kurt Warner decided to retire and Anquan Bolden was traded. Wells is at the forefront of that image change.
With Russ Grimm in charge of the running game, expect Wells to power his way up the middle and also excel on runs off tackle.
If injuries don't set him back, he'll force Tim Hightower permanently into a third down back, giving him even more carries. If everything goes right, Wells could finish the year with around 1,200 yards.
LaDainian Tomlinson might be gone from the Charger back field, but Mathews will make Chargers' fans quickly forget about the former superstar's departure.
If scientists cloned LT as a running back, Mathews might be the product of the experiment. He is an elusive, albeit powerful back like Tomlinson was in his early years. He hits the holes fearlessly and can burn defenders in space.
Mathews even wore No. 21 in college to honor the Charger great.
Expect Norv Turner to feed the Fresno State product often at the beginning of 2010. If he excels, he'll give San Diego a needed charge in the run game after LT proved inefficient last season.
If it goes to plan, Mathews most likely will win Offensive Rookie of the Year and rush for well over 1,000 yards.
When he's given the opportunity, Jones has looked like one of the top dynamic playmakers in the NFL.
But injuries and a crowded backfield have never allowed the Dallas running back to shine. With Marion Barber slowing, however, this could be his year.
Some say Jones can be the Chris Johnson of the NFC. His acceleration is outstanding and he has the shiftiness to make defenders miss in the open field.
Jones put on a few pounds of muscle in the offseason to try to deal with the wear and tear of the NFL. If he can stay healthy, he'll receive plenty of touches in the Cowboy offense.
The starting position looks to be Jones' to lose. With an injury-free season, he should bust onto the NFL scene this season.
The Jets' run to the AFC Championship game was an unexpected and impressive feat, and Greene was a huge factor in that.
The third round rookie out of Iowa pounded opposing defenses to the tune of 304 postseason rushing yards, including two 125+ yard games against Cincinnati and San Diego.
Those performances, along with Thomas Jones' departure, make Greene the hot pick to breakout in 2010. With arguably the NFL's top offensive line ahead of him, Greene will have plenty of space to work with.
The Iowa running back has some power in the trenches, but possesses elite agility and speed on the edges.
Some question his durability after suffering a rib injury in the AFC Championship. Whether or not that is warranted, Greene will still shine in 2010.
With a hungry offensive line in front of him, the downhill runner should have the type of breakout year Ray Rice had in Baltimore last season.