Running backs have become outcasts in the NFL. Choruses of “running backs don’t matter” ring out every time a backup running back comes in and racks up a bunch of yards. Now the Minnesota Vikings are taking their turn at this course. Alexander Mattison has stepped in with Dalvin Cook nursing twin ankle injuries. He took over the entire Week 5 win against the Detroit Lions, putting up over 100 on the ground. On the surface, the run game seemed to function well with Mattison carrying the rock. Since Cook is on a five-year, $68 million deal, will the Vikings look to shed the money and turn to Mattison full time?
There are many ways to answer this, and none of them make the idea look very good. Statistically, the run game has suffered demonstrably. On tape, you can see the difference between Mattison and Cook. Saving cap space is always nice, but the contrast between the two running backs is too stark to justify such an aggressive move.
The Statistical angle
Mattison’s 268 rushing yards look reasonable on the surface. He has averaged 3.9 yards per carry, with Cook averaging 4.5, which is pretty close. However, keep in mind that 48 of those 268 yards came on a single run. That’s 18% of Mattison’s entire season. We shouldn’t discount that 48-yard scamper. Mattison earned those yards. So instead, let’s turn to some of the more advanced stats to help clarify the picture.
There is a lot more contributing to the success or failure of a run game than the running back. Even still, comparing the two backs’ carries statistically illustrates a big divide. From an EPA perspective, only one running back has produced a positive EPA performance on the season. Cook’s Week 2 performance generated 1.2 EPA, which is especially impressive for a run game, typically a negative EPA proposition.
Dalvin Cook runs lose 0.13 EPA per play on average, and Mattison runs lose 0.28. Both figures are poor thanks to other issues with the run game, but Mattison falling short of Cook by that much is immensely concerning. Mattison runs have been twice as bad as Cook runs. If Cook were fully healthy, the lead would only increase.
But some explosive plays warp averages and skew our perceptions. To adjust for this, we can examine success rate. Success rate is a binary measure that tells us if a play got the team closer to scoring or closer to giving the ball back. Today, I’ll be using Ben Baldwin’s definition for success rate, which uses positive or negative EPA to make the distinction.
Cook’s success rate is comfortably above Mattison’s, even with Cook playing through injury for much of the season. Pre-injury, Cook’s success rate jumps above 40%. Post-injury, it only dips to 29%.
The statistical angle does not reflect well on Mattison, but stats never tell the whole story. What if Mattison runs happen to have worse run blocking? It’d be a factor of luck that would excuse the poor runs. What if Mattison runs come against more stacked boxes or in worse down-and-distance situations? The Vikings led for most of the two games Mattison started, Week 3 against the Seattle Seahawks and Week 5 against Detroit. Maybe there’s a hidden factor?
Let’s Go To The Tape
Unfortunately for Mattison (and the most ardent fans of salary-cap space), the tape does not reflect any better on him. We’ll forgive Mattison for his fumble against Detroit in Week 5 since Cook had a game-altering fumble of his own in Week 1. But we won’t ignore the poor running that led to the fumble.
In fairness to Mattison, there is a linebacker on the 25 who probably destroys any attempt to get a first down. But even still, it is highly blameworthy to ignore a coaching point and expose yourself to a turnover by doing so.
That was a unique situation, but it displayed a problem Mattison struggles with repeatedly. The offensive line has given him no shortage of adequate run blocking, but Mattison routinely declines responsible gains in favor of the bigger play. In a vacuum, that may not be so bad, but Mattison isn’t the kind of athlete who can bounce a run around the corner for an explosive play. His best play on the season involved him crashing through bodies with his physicality, not his burst or acceleration.
Running backs come in many styles in the NFL. You can be a short, shifty scat back. You can be a one-cut-and-burst sprinter. Mattison is a physical back. His game is predicated on bashing tacklers to fall forward for extra yards or hurdling them altogether. So when Mattison tries to embody the style of his teammates, it can turn reasonable gains into failed plays.
We talk a lot about vision when it comes to running backs. That’s more complicated than simply running through the open hole. Reads depend on his blockers’ leverage, the play itself, and what sort of front the defense deploys. For zone runs, most reads can be broken into three categories: bang, bend, and bounce.
If the running back sees an opening in the first hole he looks at, that’s a bang read. For inside zone, that’s usually an A gap (between the center and guard). For mid zone, that’s the B gap (between the guard and tackle). Outside zone angles at the C gap. Anything to the outside of the intended gap is a bounce read. Anything to the inside or back side is a bend read, which often looks like a cutback. There are always exceptions, but this architecture works for a baseline.
Zone runs do have an initial plan, but the play design doesn’t decide much more than that ahead of time. If you see a stat about a team running more up this gap or that gap, that’s usually a decision the running back is responsible for. If those decisions are bad, the coach can try to direct the back otherwise, but it’s on the player in the moment.
These reads need to be simple so that running backs can make them in split-second windows. If the blocker has the right leverage, bang the read. If he doesn’t, bounce or bend accordingly. It takes extremely quick processing and acceleration to hit those holes. In the run game, blocks can’t sustain for much longer than a fraction of a second. Lanes close quickly.
Mattison’s indecisiveness makes it impossible for the play to work out. More frustratingly, it wastes otherwise well-orchestrated plays. Run plays are hard to execute flawlessly, with several linemen responsible for their own failure opportunity. When they all perform well but the running back can’t harvest the crop, it’s enough to drive a coach crazy.
Mattison’s athleticism also limits the run game. He has adequate speed, but there isn’t much functional burst on the field. He is strong, which makes him a good backup running back, but that’s difficult to build an offense around.
Even with Cook’s ankle injury, he’s been more adept at weaving through the tight lanes of a typical run play. For the long term, building a running game around Mattison would be career suicide for Klint Kubiak, Rick Dennison, and anyone else involved. If the Vikings want to get cheaper at the running back position, they’ll need to spend another draft pick or hope Kene Nwangwu is a superstar in waiting. Mattison shouldn’t be more than a backup until he cleans up this bevy of issues.