The most grueling and hard-hitting offensive position in the NFL is undoubtedly running back. Play after play a rusher is asked to take on defensive lines and if they can break past that first barrier, speedy defensive backs have already built up enough momentum to stop their progress dead.

It’s a position with a small window for success, with most rushers considered past their primes after the age of 30 due to the toll they take. But its still one of the most exciting positions in the league, one that only a handful of players can really excel at.

It’s become difficult to predict just who will be the best back year-to-year, given no player has led the NFL in rushing in back-to-back seasons since 2007, and many teams splitting up carries between two running backs to maintain health and fresh legs.

But there are 10 running backs worthy of being called the best in the NFL, and we’ve broken down our list for who will be the top dog in the 2015 season. The honorable mentions who just missed out on our list include Cincinnati’s Jeremy Hill, Miami’s Lamar Miller, Denver's C.J. Anderson, Baltimore’s Justin Forsett, Indianapolis’ Franke Gore, and New Orleans’ Mark Ingram.

1.Jamaal Charles, Kansas City Chiefs

The dynamic playmaker had only 206 attempts last season, his lowest total since his rookie year in 2008. But its Charles' versatility and the addition of receiver Jeremy Maclin that should make him the top running back in 2015. He still put up 1,033 yards and nine touchdowns over 15 games, ranking fourth among running backs at 5.0 yards per carry, and caught another 40 balls for 291 yards and five more scores. In his second season under head coach Andy Reid, Charles should have a better understanding of the offense and lead the league in total yards.

2.Le’Veon Bell, Pittsburgh Steelers

Finished second in the league in rushing last season, and is rated No. 2 due to his potential three-game suspension to start 2015. Bell could come close to his 2014 production of 1,361 yards and eight scores with a whopping 83 catches for 854 yards and three touchdowns, thanks to his quick feet, excellent hands and power, but 2015 is the year Bell must prove if he’s the real deal or just a flash in the pan. The Steelers elite passing game should create opportunities for Bell to thrive in 2015.

3.Adrian Peterson, Minnesota Vikings

A year away from the NFL might have done wonders for Peterson. He should be fresh and ready to take the NFL by storm with his incredible power and breakaway speed. Quarterback Teddy Bridgewater may need to make big strides in his second season with receivers Cordarrelle Patterson and Charles Johnson so that defenses don't focus too heavily on containing Peterson.

4.Marshawn Lynch, Seattle Seahawks

Lynch is in line for his fifth straight 1,000-yard season and seventh in his career. But touchdowns might be hard to come by with the addition of tight end Jimmy Graham. "Beast Mode" is 29 years old, and could show signs of slowing down, but he is playing in an elite offense that continues to have Super Bowl hopes. The Seahawks will continue to give Lynch plenty of carries in 2015.

5.Eddie Lacy, Green Bay Packers

Lacy’s size, strength and quarterback put him in position for a third-consecutive 1,100-yard season. He also improved as a pass catcher with 42 receptions for 427 yards and four scores in his just his second year. Lacy’s 4.6 yards per carry, up from 4.0 his rookie year, stands out most and along with ability to break tackles for those extra yards. He should have another big season.

6.DeMarco Murray, Philadelphia Eagles

This might seem too low, but how Murray adjusts to life in the NFL without the Cowboys stellar frontline could determine the Eagles fate next season. Murray was far-and-away the best back in the league last season, with his 1,845 yards nearly 500 more than the No. 2 rusher Bell, and he converted 85 runs into first downs. But he’ll also have to share the ball some with Ryan Mathews, and Murray’s learning an entirely different and much faster offense under head coach Chip Kelly.

                           Arian Foster Texans 2015 Getty Houston's Arian Foster returned to form last season, but the lack of a top quarterback pushes him down to No. 7 in 2015. Photo: Getty Images

7.Arian Foster, Houston Texans

Foster posted three of the best seasons we’ve ever seen from 2010 to 2012, but was derailed by injuries in 2013. He came roaring back last season with 1,246 yards and eight scores over 13 games. At this point, he might be a bit underrated. But with Houston weak at quarterback and wide receiver, Foster’s workload might be too much and defenses will really focus on him. Nevertheless, he’ll still be a top 10 back by season’s end.

8.Alfred Morris, Washington Redskins

A durable tank of a back who hasn’t missed a game in the first three years of his career, Morris gained more than 1,000 yards for the third straight season despite three different starting quarterbacks in 2014. His best year was 2012, when Robert Griffin III was healthy and equally amazing, so Morris’ play is very much tied to his quarterback. If RG3 stays healthy and plays well, Morris could find himself in the top five soon enough.

9.Matt Forte, Chicago Bears

In the midst of a contract year and turning 30 in December, Forte’s gunning for a new deal after racking up his third-straight 1,000-yard season and snagging a career-high 102 receptions for 808 yards and four scores. Forte’s elusiveness and power make him difficult to tackle and he should still put up solid numbers, but quarterback Jay Cutler’s uncertain future and the addition of rookie back Jeremy Langford slightly diminish Forte’s overall potential in 2015.

10.LeSean McCoy, Buffalo Bills

After he was traded by Philly, McCoy instantly became the Bills best playmaker just ahead of second-year receiver Sammy Watkins. He’s put up 2,926 rushing yards and 14 touchdowns the last two years, but McCoy’s now behind an offensive line that was No. 25 in the league in rushing last season and Buffalo lost some line depth in free agency. McCoy should get plenty of touches, but with so many questions at quarterback in Buffalo his numbers will decline just enough to make him No. 10 in the league.