Comparing Thomas Rawls to other out-of-nowhere running backs

Thomas Rawls was one of the breakout stars of the 2015 NFL season, while quickly entrenching himself as the heir-apparent to Marshawn Lynch in the Seahawks' backfield.

He also represents yet another success story from an un-drafted/lowly-drafted running back in his first year that received a legitimate number of touches. This got me to thinking about how Rawls might compare to some of those other players.

While we can't definitely say what 2016 will hold for Rawls, we can take a look at some numbers and try to predict his future. We're going to break down all of the lowly-drafted (5th round or later) and un-drafted free agent running backs from the last decade or so, and see if there is any correlation in their statistical outputs from year one to year two. For the sake of holding myself to some sort of sample size standard, only seasons with upwards of 100 touches will be used.

The three metrics we'll use for this exercise are Football Outsiders' DYAR (defense-adjusted yards above replacement), DVOA (defense-adjusted value over average) and success rate. In case you're unfamiliar, each of these stats can be summarized pretty simply:

-DYAR: how many more yards the player put up that season than a replacement-level player in the same situations.

-DVOA: how much more successful the back was per play than a league-average back in the same situations.

-Success Rate (as written by Football Outsiders): "represents the player's consistency, measured by successful running plays (the definition of success being different based on down and distance) divided by total running plays"

To learn more about each of these statistics, I implore you to check out the page I pulled this data from on Football Outsiders, and check out their more in-depth explanation of their statistics. But for now, to the data!

My initial thoughts here are, holy crap, Thomas Rawls was even better than he looked on television. His numbers as a whole surpass every other player on this list in any single season, and the only single category he was bested in was DYAR by Alfred Morris in 2012 and Arian Foster in 2010. So we're already moving into uncharted waters with Rawls as it is.

The second thing that jumps out is that no matter how talented the back may have become later in their career or how great they were in their first season, there is a very apparent negative correlation between the year one and year two statistics. From year one to year two, the average of all three measured statistics dropped. The drops in DYAR were particularly noticeable. (the chart here might need a second to load).

Are these statistics perfect measures of these running backs? No. For one, these numbers only take into account their performance when running the football, and there are plenty of guys on here who have done a ton of damage throughout their careers through the air. But, it's hard to ignore such clear trends. There are also definitely some skews in the numbers thanks to Foster's other-worldly 372 DYAR in 2010, and Andre Ellington's brutal fall from grace over 2013 and 2014. Alas, this is how numbers work, so we push forward.

One possible explanation for the numbers appearing the way they do, is the fact that these players were all drafted in the fifth round or later, or not at all. They weren't players that opposing coaching staffs focused on as they dug into their offseason preparations for the season. It's similar to the surprise rookie pitcher in baseball that wasn't highly-touted on his way up, and was therefore able to sneak up on opponents until there was enough of a sample size to really analyze him (as a local example, think Mike Montgomery or Roenis Elias for the Mariners).

I'm not sure I truly buy into that idea, since football is a sport that doesn't hinge as much on individual performances as baseball does, but I'm sure it at least plays a small part as far as a defense being unprepared for a certain running style.

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What does all of this mean for Thomas Rawls? First off, as I noted earlier, Rawls is unlike any of these backs before him. His numbers and his overall effectiveness according to said numbers are superior to everyone else on the list, with Arian Foster's 2010 season probably being his top competitor. So it's possible that Rawls is the guy from the last decade or so who will be able to overcome the negative trend and continue his ascension in the NFL. However, considering the injury at the very least, Seahawks fans should probably be prepared for some sort of drop.

Using the average drop in each statistic from year one to year two, one would expect Rawls to drop 94.55 points in DYAR, 11.99% in DVOA and 4.45% in Success Rate. Even with that drop, however, Rawls can reasonably expect to put up a 122.45 DYAR, 14.61% DVOA and 57.55% Success Rate, as low-end projections. Even with those likely worst-case-scenario numbers, he would be miles ahead of every other running back on this list in his second season, and would still be one of the better seasons if put up against everyone's first season.

I, nor the numbers, truly know what we can expect from Thomas Rawls in 2016. The injury certainly doesn't help, and there's no telling whether or not Seattle will add a piece like Matt Forte or Foster to the backfield (unlikely, in my opinion). However, while the two year trends for running backs with similar backgrounds to Rawls aren't terribly promising, his talent was transcendent enough in 2015 to set himself up to succeed despite a potential drop in efficiency in 2016. Or perhaps he could be the back who bucks the trends altogether.