The threat of the run—and not actually the yardage picked up by two of the best running games in the NFL—will ultimately decide the final Wild Card Game of the year between the Seattle Seahawks (11-5) and Washington Redskins (10-6) on Sunday afternoon.
That's not to say that Seattle's Marshawn Lynch and Washington's Alfred Morris, two of the most productive running backs in the NFL, won't have a significant impact on the game—they will.
However, it will be the ability of their rookie quarterbacks—Russell Wilson and Robert Griffin III, respectively—to sell the run effectively that will have the biggest impact of all.
Defenses have to defend against the run with Lynch and Morris on the field. The ability to freeze linebackers and safeties as their receivers run free behind the defense has become an integral part of both Wilson and RGIII's success.
According to Pro Football Focus (subscription required), there wasn't a pair of quarterbacks who utilized play action as frequently as this pair of dynamic rookies. Also, 36 percent of Wilson's dropbacks were play action, while Griffin—at 39.1 percent—led the NFL.
Not only do defenses need to be wary of Lynch and Morris, but both quarterbacks are more than happy to tuck the ball under their arms and take off running themselves.
Combined, the duo carried the ball 214 times for 1,304 yards and 11 touchdowns—averaging better than six yards per carry during the regular season.
That only makes things far more difficult on a defense.
While Seattle's defense has done a far better job of defending against the pass than Washington has, both units must be on their toes in this one.
With the amount of play action that is going to be called, the Redskins—who have the older, more experienced unit—might actually be in better shape to defend against it than the younger, more athletic Seahawks unit.
Still, whichever defense can win the battle of discipline required to not fall for the play action will be the defense that lives on to play another week.
It's going to be a battle worth watching.