Jerick McKinnon could help save the season.

The Vikings, despite being down their starting quarterback and starting running back are still in position to make a serious playoff push. While it’s still early in the season, it’s relevant that they’re currently holding home field advantage in the playoffs as the NFC’s second team.

That kind of play — two wins in the last two games without either the passer or runner they intended to start the season with — is surprising and driven both by unexpected performances from Case Keenum and McKinnon.

We’ll see how sustainable McKinnon’s performance is, but for now his play has served as a fantastic fill-in for second-round draft pick Dalvin Cook. With 245 yards from scrimmage and three touchdowns on only 44 touches, McKinnon has been a critical part of the Vikings’ success.

This is a good turnaround from the ire he was earning from Vikings fans in the first four games of the season, where he averaged 2.6 yards per attempt and was responsible for two fumbles.

It seems, however, that more people were disappointed in his kick return duties, one of which led to a fumble, and the lone snap he had as the option quarterback, where the running back-quarterback exchange led to the other fumble.

The Vikings have started drives on their own 24 after kickoffs on average, tied for 23rd in the league. While it’s not catastrophically bad, it’s certainly been questionable and has driven a lot of the antipathy Vikings fans had for McKinnon’s play.

Solely as a running back, McKinnon wasn’t lighting up the league, but with only 10 carries in the first four games, it’s kind of unusual that people were willing to give up on the Georgia Southern alum — particularly given his usefulness in the passing game. Cook only averaged 2.9 yards on his first 10 carries and no one was worried because that would have been absurd.

Now that McKinnon has averaged 5.1 yards per carry over the past two games, has he become good again? That more closely matches his 2014 and 2015 rates, as well as his end-of-season 2016 production.

Despite matching his previous season’s performances, there’s still reason to be a little bit wary of his yards-per-carry numbers. The first reason is obvious — 31 carries is hardly a good sample either. Not only that, yards-per-carry is notoriously unstable and a poor indicator of running back performance.

At the low and high ends, it’s pretty good. A 2.0 yards-per-carry back is substantially worse than an 8.0 yards-per-carry back, but there’s not much weight behind the idea that a back averaging 4.7 yards-per-carry is much better than one averaging 4.5 or possibly even 4.3.

A big reason for that is role; a running back who is good at converting third-and-short and goal line runs is going to help his team immensely, but his use there is going to drop his average. Not only that, an offense with a talented quarterback is going to pass more often on ambiguous downs, like first-and-10, where it’s a little easier to rack up additional yards.

Yards-per-carry also doesn’t value consistency. In a system where teams have to functionally re-establish possession every four downs, a 50-yard run followed by three runs of 0 yards is significantly less valuable than two runs of 12 yards and two runs of 13 yards — both end at the same yardage marker on the field, but the first series ends on fourth down and (likely) a field goal try, while the second one ends on first down and more opportunities to score.

To address those concerns, I’ve looked at two statistics — yards over expectation (to deal with the ease of running at certain down and distances) and success rate (to measure consistency). These are statistics I’ve covered before.

In short, yards over expectation tells us how good a running back is at what he’s asked to do, and success rate tells us how consistent a running back is at getting minimum yardage.

Both measures are impacted by the offensive line, so we can look at some other statistics that help remove the influence of blockers, like yards after contact, in order to provide some additional context.

Player Yds Per Carry Yds vs Expected Success Rate Overall Rank Mike Gillislee 4.36 4.55 63.6% 1 Aaron Jones 5.19 5.30 53.1% 2 Marshawn Lynch 4.24 4.20 60.0% 3 Le’Veon Bell 4.81 4.88 53.2% 4 Mark Ingram 4.56 5.02 52.0% 5 Leonard Fournette 6.35 6.69 36.7% 6 Adrian Peterson 5.15 5.09 50.0% 7 Ezekiel Elliott 4.00 4.43 55.2% 8 Derrick Henry 6.09 6.04 39.1% 9 Javorius Allen 3.94 4.22 54.8% 10 Orleans Darkwa 6.41 6.05 37.9% 11 Todd Gurley 4.30 4.34 51.4% 12 LeGarrette Blount 5.04 5.20 42.9% 13 Doug Martin 4.70 4.96 44.4% 14 Jay Ajayi 4.06 4.03 51.0% 15 Wayne Gallman 4.20 4.55 45.0% 16 Jordan Howard 4.42 4.29 45.5% 17 Jerick McKinnon 5.13 5.10 37.5% 18 Isaiah Crowell 4.21 4.26 44.8% 19 Lamar Miller 3.83 3.81 46.7% 20 Alex Collins 4.78 4.44 33.3% 21 Tarik Cohen 2.25 2.44 50.0% 22 Melvin Gordon 4.18 4.31 33.3% 23 DeMarco Murray 3.77 3.61 38.5% 24 Frank Gore 4.04 4.07 33.3% 25 Kareem Hunt 3.37 2.78 39.5% 26 Carlos Hyde 1.86 1.73 40.9% 27 Ameer Abdullah 3.54 3.38 20.8% 28 Latavius Murray 2.19 2.37 29.6% 29 Elijah McGuire 2.00 2.17 19.0% 30 Jonathan Stewart 0.65 0.24 11.5% 31

McKinnon has been one of the most effective backs at getting yards, but he’s also been one of the most disappointing at generating consistency. Overall, that puts him 18th among running backs with at least 20 carries in the last two weeks.

Dalvin Cook’s absurd success rate of 61.0 percent would have ranked first among these players and his yards over expected of 4.84 would have ranked 11th. Together, Cook would have ranked first overall because of how incredibly good that success rate is.

This tells us that McKinnon is explosive but not necessarily consistent. That’s not surprising; remove a 58-yard run and McKinnon’s average over the past two games drops to 3.42 yards per carry.

How much of this is on the offensive line? If we compare him to Murray, who has a similar success rate but less explosiveness, we could surmise that the line has been blocking poorly. But Cook has an incredible success rate with the same line blocking for him.

McKinnon’s 2.56 yards after contact per carry in the last two weeks is just above average for running backs. In that time span, he’s forced about one missed tackle for every eight runs, which is again about average.

Given that Cook was well above average in that capacity, there’s some evidence that the offensive line isn’t doing a lot to create yards — and Cook has just been astounding at overcoming that obstacle.

So, how has McKinnon looked on film — does it confirm our soft conclusions?

I looked at the runs in the Green Bay game, and there’s a lot of good and bad. There are moments where we see the sheer athleticism of McKinnon is enough to create a big run. The best example is this draw:

We also got to see some more of that throughout the day, including a run with a wicked stiff-arm to overcome an unfortunately awkward blocking situation that freed up Nick Perry:

But we also saw what looked like poor decisionmaking on McKinnon’s part.

Below is a difficult decision that McKinnon ends up getting wrong in large part because of how much he trusts his athleticism. The A gap between Pat Elflein and Joe Berger is the intended gap, and it closes quickly.

It’s squeezed somewhat successfully by the opposing defensive tackle, but it still would have been a better choice to gut out the narrow gap up the middle than bounce outside into a safety.

That’s not an egregious example, and there aren’t many, but below is another clearer moment where he could have done more to generate yards.

McKinnon stepped out of the gap he needed to run up on, perhaps because of Blake Martinez hanging overhead. But the draw worked; Martinez dropped into a deeper zone in response to a pass that was never coming. McKinnon should have challenged him.

In good news, the intuition that he’s not much value on inside runs has proven to be false thus far; players generally average 20 percent more yards per carry on outside runs and McKinnon’s improvement is only a little bit more, 27 percent.

Looking on film, McKinnon does have a small tendency to bounce outside but it’s not much more than most running backs entering the NFL and he takes contact head-on more often than not — something we saw quite a bit of in the Bears game.

There are runs where the offensive line is wholly responsible for the failure and other runs where McKinnon creates yards that shouldn’t be there, but the two qualities of athleticism and decision-making might best define his upsides and downsides.

At the moment, this will continue to result in the volatility we see from him as a back: low success rates — caused in part by his decision-making or the offensive line in front of him — and explosive runs.

Now in his fourth year, it might be a bit much to ask his vision as a running back to improve. Instead, the Vikings may need to settle for a little bit of inconsistency even as the offensive line improves. In return, they could get some pretty good big plays.