Who’s the best running back in football? For the first time since the days before Jim Brown, there isn’t an obvious answer to the question.

This is a title that’s normally claimed during the middle of the season from its previous holder. Do you remember the 2008 season? LaDainian Tomlinson had just won his second consecutive rushing title and led the league in rushing touchdowns for the second consecutive season. He was still the first pick in fantasy drafts that year, and unquestionably the best running back in football. Adrian Peterson had begun to enter the discussion with that legendary 296-yard game against the Chargers halfway through his rookie season in 2007, but he followed that game with just 80 carries for 305 yards over the second half of the year. It wasn’t quite his moment, but it seems obvious in hindsight that Peterson’s ascension was a matter of time.

Halfway through the 2008 season, things officially shifted. Peterson busted out a 192-yard game against the Packers in a 28-27 thriller in Week 10, one that put him over the 1,000-yard rushing mark with seven more games to go. Tomlinson had just 629 yards and wasn’t even averaging four yards a pop. At the time, Tomlinson was 29 and struggling through a disappointing season with a legitimately great quarterback, Philip Rivers, running his offense. Peterson was 23 and dragging Gus Frerotte to victories. It wasn’t just that one game, but the preponderance of evidence clearly pointed in Peterson’s direction. He was the guy. Peterson held the title from 2008 through Week 16 of last season, when he tore up his knee in a meaningless game against the Redskins. Challengers have risen, but nobody’s grabbed the title away from Peterson the way that he took it away from Tomlinson.

There’s usually a very obvious transition between titleholders over the course of one given season. Of course, this entirely arbitrary title is in the eye of the beholder, but with a mix of statistical information and a dollop of common sense, I think the vast majority of fans at the beginning of any given season would have chosen one player as the best running back in football. Personally, I believe that there have been 14 players since the 1970 AFL-NFL merger who have reigned as the best running back on the planet.

Player Took Over Loses Title Larry Brown 1970 1973 O.J. Simpson 1973 1977 Walter Payton 1977 1978 Earl Campbell 1978 1981 Tony Dorsett 1981 1983 Eric Dickerson 1983 1989 Barry Sanders 1989 1991 Emmitt Smith 1991 1994 Barry Sanders 1994 1997 Terrell Davis 1998 1999 Marshall Faulk 1999 2002 Priest Holmes 2002 2004 Shaun Alexander 2004 2006 LaDainian Tomlinson 2006 2008 Adrian Peterson 2008 2011

Of course, that table is probably worthy of another set of articles all by itself. You might argue that O.J. Simpson outplayed Larry Brown in 1972, when Simpson won the rushing title and Brown picked up the MVP on a much better team. That’s fine. Maybe you wedge a run for Jamal Lewis in between Marshall Faulk and Priest Holmes. You can make the argument that Emmitt Smith and Barry Sanders traded the title more than once between 1991 and 1996. I’d buy it. You can question whether Walter Payton was a better back than Earl Campbell during Campbell’s rookie season in 1978. You can also probably angrily shout in the comments that the second-greatest running back in the history of football was the best back in the league for more than one lone season during his career. You might be right.

If you asked 1,000 fans who the best running back in football was going to be in 2012, though, I think nobody would get more than 35 percent of the vote. Fantasy football isn’t a fair proxy for the real thing, but there’s more deviation for the first pick in this year’s drafts than there’s been since 2008. There simply is no clear-cut no. 1. I am taking it as my duty to figure out who that top back is going to be.

There’s no complex formula or algorithm to identify which one particular player is about to raise his game and become a truly elite halfback. Past performance matters, and younger players are more likely to undergo a dramatic improvement than older ones, but the attrition rate for running backs is just overwhelming. Of the 10 leading rushers in the NFL during the 2008 campaign, when Peterson marched his way to the top, just one — Michael Turner — also finished in the top 10 last season. That’s not a one-year fluke, either. Three guys in the top 10 in 2005 made it back into the top 10 in 2008, and three from 2002 made it to 2005. It’s impossible to reliably project future injuries for a given player, but health is a skill and running backs age awfully fast.

In addition, you have to consider the changing times when determining who the best back in football will be. In 2011, more than 57 percent of offensive snaps were pass plays. That’s the highest percentage since 1995, and 1995 was a world in which teams were much more comfortable giving one back the bulk of their carries. During that season, the 10 backs in football with the most carries averaged 329.4 attempts; in 2011, only one back (Maurice Jones-Drew) had that many carries. The top 10 backs from last season averaged a mere 284.8 carries. Peterson was a workhorse in Minnesota, but he was rarely more than an afterthought as a receiver out of the backfield. Our new top back doesn’t need to necessarily carry the ball as a runner 350 times per year, but he should pick up plenty of meaningful touches as a receiver.

With all that in mind, I’ve identified five candidates who I believe to be the most likely to take over the title of “best running back in football” by the end of the 2012 season. It is my firm belief that one of them will ascend from the pack and justify that title, and if history is any guide, he’ll then be regarded as the best of his breed for two or three seasons. In alphabetical order

The Candidates

Matt Forte

Strengths: Has the longest track record as a starter of any of our candidates, having served as Chicago’s starting halfback since his first game as a pro. Rushing average has improved from 3.6 yards per carry in 2009 to 4.9 yards last year. Has arguably had the least help around him of any back in pro football, especially during his first two years with the team. History of remaining healthy, with 60 consecutive games started as a pro before missing the final four games of the 2011 season with an MCL sprain. Offensive line should be better with a healthy season from 2011 first-round pick Gabe Carimi, making Forte’s life easier in 2012.

Weaknesses: Best season came as a rookie in 2008, when he finished third in yards from scrimmage; hasn’t finished higher than 10th in that category since, and is yet to have a season where he finished in the top five for rushing yards. Has put up terrible numbers at the goal line; part of that is the offensive line, but other players have terrible offensive lines, too, and haven’t been as bad there as Forte. In 2009 alone, he scored 5.7 touchdowns fewer than a league-average back given his number of carries inside the 5-yard line. Has scored once every 48.3 carries during his time as a pro, the fourth-worst figure among the 35 backs with 500 carries or more over that time frame.

Arian Foster

Strengths: Most yards from scrimmage of any back over the past two seasons despite missing three games with a hamstring injury last year. Performance didn’t slip last year while Matt Schaub and Andre Johnson were injured, even though teams were undoubtedly keying on the Houston running attack. Ran for 285 yards and three touchdowns on 51 carries in the Texans’ two playoff games last year. Is the third option in a very good passing attack. Generally an awesome dude.

Weaknesses: Plays in an offensive scheme (the Denver zone-blocking attack) famous for creating monsters out of unheralded backs like the undrafted Foster. There are questions about how much better he is than backup Ben Tate. History of nagging leg injuries. Developed a (possibly unfair) reputation as a fumbler in college and, after holding on to the ball very well during his breakout as a pro, suddenly started fumbling during the second half of last season; after zero fumbles on 202 touches before Houston’s bye week, Foster fumbled six times on 188 touches. Right side of his offensive line departed as free agents this offseason, which could lead to some blocking issues as the new guys get comfortable.

Maurice Jones-Drew

Strengths: Along with Michael Turner, the closest thing to a traditional, old-school running back in terms of usage patterns left in the NFL. Difference between Turner and MJD is that the latter is actually productive. Led the league in both rushing attempts and yardage while averaging a very respectable 4.7 yards per carry, the ninth-highest average for a carry leader in league history. Did this without any semblance of a passing game whatsoever around him. Notably stout as a pass blocker (ask Shawne Merriman). Despite concerns that his 5-foot-8 frame wouldn’t hold up in the pros, has missed just three games in six seasons.

Weaknesses: Is the oldest of our five candidates and already has nearly 1,500 carries under his belt. His 343 carries from last year aren’t exactly a positive indicator for 2012; the average back with a 300-carry season from 1990 to 2010 followed that season by producing an average line of 266 carries for 1,113 rushing yards. Additions of Justin Blackmon and Laurent Robinson likely mean more passes and fewer carries to go around, and if there’s a reduction in his role, it’s hard to imagine MJD getting plaudits as best back in football.

LeSean McCoy

Strengths: A touchdown machine on an offense that was famously awful near the goal line. Led the league in rushing DYAR by a wide margin, as second-place back (Marshawn Lynch) was closer to 18th than first. Wildly efficient and consistent runner who almost never fumbles. Youngest candidate of the five, having just turned 24 a few weeks ago.

Weaknesses: Just one of the many weapons that the Eagles offense enjoys; the likes of DeSean Jackson and Jeremy Maclin take the focus away from him. Undoubtedly benefits from having a rushing quarterback in Michael Vick under center; has averaged 5.2 yards per carry in games where Vick starts and just 4.2 in games where Vick was unavailable since both took over as starters in 2010. Eagles are unlikely to give him 400 touches in a season and will probably limit him to 330 or so, preventing McCoy from putting up lofty numbers in terms of total yardage. Has already lost his best offensive lineman, left tackle Jason Peters, for the upcoming season due to injury.

Ray Rice

Strengths: Essential part of an offense that often lacked for weapons before the arrivals of Anquan Boldin and Torrey Smith last season. Hasn’t missed a game since taking over as the starter in 2009. Security blanket for occasionally overmatched Joe Flacco; no running back in football has more receptions or receiving yards than Rice does since he entered the starting lineup. Has 5,885 yards from scrimmage over that time frame, leading the NFL by more than 300 yards. Finally got the goal-line work after Willis McGahee departed last season and doubled his career rushing touchdown total, filling in the last gap in his production résumé. Still only 25. Never fumbles

Weaknesses: Unless he’s in the playoffs; has three fumbles on 136 postseason touches despite accruing just three across 1,209 regular-season touches. Probably just random chance, but every Ravens fan will worry about it until the problem corrects itself. Has split carries with another prominent back every year as a starter. Occasionally struggles in pass protection. Just lost guard Ben Grubbs to the Saints in free agency.

The Numbers

Statistics don’t form the entirety of this debate, but it’s interesting to examine some of the narratives that surround these players and determine how accurate they actually are.

Let’s start with the issue of workload. Which of our five candidates has accrued the highest percentage of his team’s touches, yardage from scrimmage, and offensive touchdowns?

The figures below — and elsewhere in the tables during this section, unless mentioned otherwise — include those years when each guy was the clear no. 1 back on his team, so it includes 2008-11 for Forte, 2009-11 for MJD and Rice, and 2010-11 for Foster and McCoy.

Player Touch % Yardage % TD % Matt Forte 46.2% 31.9% 24.6% Arian Foster 46.3% 32.6% 37.5% Maurice Jones-Drew 52.1% 35.7% 39.1% LeSean McCoy 46.0% 28.5% 38.2% Ray Rice 48.0% 35.3% 25.9%

Across the board, the answer is Maurice Jones-Drew. While Forte has a reputation for serving as his team’s only hope on offense, he actually produces a lower percentage of his team’s yardage than everyone on the list besides Shady McCoy, and scores the lowest percentage of his team’s touchdowns.

You’ll also note the dramatic difference between McCoy’s yardage percentage and the rest of the group’s totals. That jibes with the popular perception that the Eagles might not “need” McCoy to produce the way that, say, the Jaguars need MJD to in order to move the football.

If a player is truly the best running back in football, he should dramatically outproduce his backups, right? Maybe. That makes sense, but the lead back in any offense has to endure the bulk of the carries while pacing himself for the workload of an entire game, while the backup can give all he’s got for two or three carries before giving way to the starter. Think of it like the relationship between a starter and a reliever in baseball; a 2.85 ERA in 200 innings from a starter is a lot more meaningful than a 2.85 ERA from a reliever in 65. In any case, it’s interesting to see just how these players have performed versus the guys behind them over their careers as starters:

Player Carry % Att Yds Avg Backup % Att Yds Avg Matt Forte 72% 1014 4233 4.2 28% 393 1473 3.7 Arian Foster 72% 605 2840 4.7 28% 230 1122 4.9 Maurice Jones-Drew 80% 954 4321 4.5 20% 244 1047 4.3 LeSean McCoy 77% 480 2389 5.0 23% 143 572 4.0 Ray Rice 68% 852 3923 4.6 32% 399 1658 4.2

Of course, Foster’s lack of performance versus his backup halfbacks stands out here, as he’s the only player to average fewer yards per carry than the guys behind him on the depth chart. That doesn’t mean that Ben Tate should be starting ahead of Foster, but I’ve already raised my concerns about Foster’s totals being a product of the Denver scheme; this chart does nothing to dissuade those thoughts. It’s clear to see again just how important Maurice Jones-Drew is to the Jaguars, and how the Ravens have kept Ray Rice fresh by incorporating steady doses of Willis McGahee and Ricky Williams over the past three seasons.

It’s not just yardage that matters; it’s where and when that yardage comes that adds meaning and context. We all know that a three-yard run on third-and-2 in a tight game means a lot more than a four-yard run on second-and-27 in a blowout. The DYAR stat mentioned above incorporates that and credits McCoy accordingly, but let’s break it down in simpler terms. Do any of our five candidates pick up a disproportionate amount of their yardage as starters in garbage time? Defining that to be those situations in which each player’s team is either winning or trailing by 15 or more points, the numbers suggest that one or two of the five guys just might:

Player % of carries % of rushing yards Matt Forte 30.4% 34.7% Arian Foster 27.1% 29.2% Maurice Jones-Drew 24.6% 25.5% LeSean McCoy 32.3% 29.6% Ray Rice 24.6% 26.4%

While MJD and Rice spend less than a quarter of their time in the backfield in garbage time, Forte and McCoy are there closer to one-third of the time. That doesn’t sound like a huge difference, but it can be 25-30 carries or so over the course of a season. And as you might expect, players usually do better when there’s a wider disparity in the scoring:

Player Yds/Carry, 0-14pt margin Yds/Carry, 15+ pt margin Difference Matt Forte 3.9 4.8 0.9 Arian Foster 4.6 5.1 0.5 Maurice Jones-Drew 4.5 4.7 0.2 LeSean McCoy 5.2 4.6 -0.6 Ray Rice 4.5 4.9 0.4

Forte averages nearly one yard more per carry in sparsely contested moments than in closer games, while McCoy strangely does worse when the pressure is (relatively) off.

Finally, let’s phrase this question a different way. The simplest, most common usage pattern for any running back involves measuring what he does on first down. Limiting it to those 14-points-or-fewer scoring margins and focusing only on last season, what did each back do when he got the ball on first-and-10?

Player Rush Atts Rush Yds Rush Avg Pass Targets Pass Cmp Pass Yds Pass Avg Touches Yds/Touch Matt Forte 94 390 4.1 23 16 145 6.3 117 4.6 Arian Foster 105 450 4.3 22 15 252 11.5 127 5.5 Maurice Jones-Drew 168 875 5.2 9 5 39 4.3 177 5.2 LeSean McCoy 94 429 4.6 25 14 144 5.8 119 4.8 Ray Rice 122 707 5.8 32 22 153 4.8 154 5.6

It’s incredible to think that Maurice Jones-Drew averaged 5.2 yards per carry on first down in relatively close situations when the Jaguars had virtually no other number to call. What, was Blaine Gabbert going to look deep for Chastin West? His primary backup, Deji Karim, averaged just 2.0 yards per carry in the same situation. That’s remarkable. Foster’s receiving production is mostly the result of a 78-yard touchdown he caught against the Titans; it’s also worth noting that Tate averaged 5.8 yards per carry on his 66 carries in these situations.

The Pick

In truth, there’s maybe a 30 percent chance that the guy listed below at no. 1 ends up claiming the popular vote, a 75 percent chance that one of the five candidates evaluated above picks up the trophy, and a 10 percent chance that somebody not named as one of the final five or in the Honorable Mention list takes the crown. Maybe Jonathan Stewart puts up some enormous contract year and runs for 1,700 yards. Or Jamaal Charles comes back with a vengeance and the Chiefs give up on trying to keep him healthy. Marshawn Lynch’s second half could be for real. Anything is possible with running backs.

But after all that, I know that I have to commit and pick through those five players. All of these guys are great, but after going through each player’s statistics and situation, it’s pretty clear to me that Ray Rice is the guy to choose. Rice is the healthiest back of these five. He’s the best receiver and has the most reliable hands. He’s been an essential part of an offense that would likely break down without him. And since he’s the second-youngest of our five backs, at 25, he still has some room left on his growth curve. And there’s virtually no argument that holds up against him. You’d like to see him get a higher percentage of his team’s carries, but with Williams retiring and McGahee in Denver, that’s going to happen in 2012. And in this version of professional football, nobody really has a heavy workload, anyway. We are in an era in which being well-rounded is perhaps more important than ever before, and nobody in the NFL is more versatile and efficient than Baltimore’s starting running back. I believe that Ray Rice will be recognized as the clear-cut best running back in football by the end of the season, primarily because he is already the best running back in football.