It's been clear that Seahawks running back had one hell of a rookie season, but asPro Football Focus' Mike Clay pointed out today, it might have been even more impressive than we even thought.

Clay did a study that looked at running back carries through the context of what type of defense that back was facing. The simple premise is that it's much easier to run at nickel/dime "passing down" defenses where teams are substituting defensive backs for defensive linemen or linebackers, than it is to run vs. base "run down" defenses.

Per Clay:

The idea here is that all runs are not created equal. Bigger/early-down backs tend to run against base defenses, while scat/third-down backs see more work against nickel and dime packages.... this provides a major advantage for the latter (in terms of yards per carry).

That's obvious. 3rd down backs might pick up 6 or 7 yards on a carry when it's 3rd and 10 and the defense is simply playing to force a 4th down.

Clay's numbers illustrate this really well. He took data going back to 2007 to establish a baseline yards per carry that running backs have seen against the different defensive personnel groupings. He then put together an "expected" yards per carry for each running back based on the defensive fronts they faced in 2015. Thomas Rawls' 5.6 YPC in 2015 outpaced his expected YPC by the biggest margin of any back in the league (1.4 YPC above his "expected" 4.2 YPC).

Per Clay:

Rawls' 5.8 yards per carry against base defenses was tops in the league among backs who carried the ball more than 45 times. Of his 147 attempts, 67 percent came when the defense had fewer than five defensive backs on the field (14th highest). Obviously super effective as a rookie, slow recovery from a broken ankle is all that could slow Rawls' emergence into a superstar in 2016.

Boomtown.

Now, this 5.8 yards per carry against base defenses is another number that we can add to Rawls' super-impressive rookie year resume. ESPN's Sheil Kapadia already noted earlier this year that Rawls averaged 5.65 yards per carry (first in the NFL) and 2.68 yards per carry after contact (also first in the NFL). Rawls became one of five backs since the merger to run for 800-plus yards and average more than 5.5 yards per carry as a rookie, joining Hall of Famer Franco Harris (1972), Adrian Peterson (2007), Clinton Portis (2002) and Maurice Jones-Drew (2006). That's good company.

All this is to say that assuming Rawls' ankle can heal up for next season, it should be fun to see what he can do in his sophomore campaign.

Here are two of my favorite Rawls' runs in 2015, which both show his elusiveness, burst, vision, and tackle-breaking ability pretty well. They also show his aggressiveness, which is a word that you hear Pete Carroll say a lot when describing the types of players he looks for.