The analytics confirm that Nebraska is Ohio State’s most explosive test yet

The Nebraska game has long been penciled in as a potential upset spot for Ohio State. The end of the Buckeyes’ season, with games against Wisconsin, Penn State, Michigan State, and Michigan, is still looming, but Nebraska has undoubtedly some of the most explosive players that Ohio State will see this regular season.

Nebraska is a top-30 team in explosiveness rate, and top-10 in explosive pass rate. Last year’s game was decided by just 5 points thanks to quarterback Adrian Martinez’s excellent play.

But the 2019 Cornhuskers have also lost to Colorado, struggled for much of the game against South Alabama, and allowed 38 points to Illinois in a 4-point win.

Given those conflicting data points, it’s reasonable to be a little confused about what to expect in this matchup. Will Ohio State see the team that allowed 15 tackles for loss from Illinois, or will they see a young, explosive team playing at home in an intimidating atmosphere?

---

Nebraska’s defense isn’t as bad as I thought

Thanks to @zane_rm of Coug Center for putting these visualizations together!

The Cornhuskers’ defense is actually a little better than I expected based on the fact that they have allowed 34 points to Colorado, 21 to South Alabama, and 38 to Illinois. But they rank:

• 36th in average defensive expected points added, or EPA (but just 56th in EPA success rate)
• 47th in defensive SP+
• 26th in overall success rate

Maybe this is just relative to the apparently low expectations I had for the Huskers defense, but Nebraska is far from terrible defensively. Cincinnati and Indiana both rank higher (31st and 36th in defensive SP+), but... still.

So what exactly are they doing well? The Huskers defense has top-30 ratings in all of the following stats:

• Per-play success rate (26th)
• Pass success rate (21st)
• Opportunity rate (29th)
• Red zone success rate (25th)
• Scoring opportunity rate (20th)
• Redzone touchdown rate (26th)
• Havoc rate (9th!)

Altogether, this suggests that the Huskers defense has been pretty solid so far on a per-play basis, especially against the pass. They’re creating a lot of havoc, which likely plays a large role in that passing success rate. In fact, they rank 6th overall in tackles for loss in the country, with just 8 fewer than Ohio State has (the Buckeyes are 2nd overall).

Opponents are only creating scoring opportunities on 35% of their drives (20th overall), and then only scoring touchdowns on 58% of redzone opportunities (26th).

It is however important to remember the opponents that Nebraska has faced so far (and we can say the same for Ohio State’s defense!), because the above stats (minus SP+) are not adjusted for opponents. Their opponents include South Alabama, Colorado, Northern Illinois, and Illinois, who rank 128th, 11th, 113th, and 40th in offensive SP+. So two of Nebraska’s opponents have ranked in the bottom 20 in opponent-adjusted offensive SP+, and Colorado (a surprising 11th!) scored 34 points in Nebraska’s one loss. And Illinois, the other moderately good offense the Huskers have faced, scored 38 in Nebraska’s close win last week. (We should also note that Nebraska lost an insane 4 fumbles last week, which accounts for a lot of why the Illinois game was close — that game is not indicative of Nebraska’s real ability!)

That’s not to completely discount Nebraska’s raw stats ratings — after all, Ohio State’s opponents rank 77th, 100th, 45th, and 99th in offensive SP+ and we still at least think the Buckeyes defense has improved regardless of the quality of opponent. Instead, that’s just why it is important to incorporate preseason projections, which mix prior-year performance and recruiting, among other factors, into the opponent-adjusted ratings early in the season.

My point boils down to — the Nebraska defense rates pretty highly in non-opponent-adjusted stats, but is likely a little more vulnerable than those stats alone suggest.

So where should the Buckeyes look to attack the Nebraska defense? I’d start with running the ball. Assuming the Buckeyes find at least some success throwing the ball so that the Huskers can’t stack the box, Nebraska rates 41st in rushing success rate this year and 61st in rushing marginal explosiveness, also ranking 54th in runs allowed of 13+ yards (7% of runs).

For example, last week Illinois only averaged 2.6 yards per pass with a 20% success rate, but had a 44% rushing success rate and an 11% rushing explosiveness rate. Illinois back Reggie Corbin had a 66-yarder.

Interestingly, opponent rarely run the ball against the Huskers when they have an option to, however. Nebraska’s opponents have only run on 51% of standard downs (which are first downs, second-and-7 or fewer, third-and-4 or fewer, and fourth-and-4 or fewer), which ranks 104th-most in the country.

So this should be an interesting test for Ohio State’s offensive line and playcalling. Not only the intimidating road environment, but also the fact that Nebraska’s defense has been creating a lot of negative plays (including a 23.6% stuff rate, 37th). Can they create enough negative plays to put the Buckeyes off schedule? Justin Fields is still relatively inexperienced for how good he’s looked. Can the road environment trip him up?

My guess is that the Buckeyes find a decent amount of success, but I still think there is a scenario where the Nebraska defense creates a few big havoc plays and frustrates the Buckeyes offensive line for part of the night.

---

Nebraska’s explosive skill players in context

As I mentioned above, Nebraska also has the best skill players Ohio State will have seen so far.

---

Overall the Huskers rank 30th in offensive SP+. They tend towards explosiveness over efficiency, ranking just 56th in success rate but 27th in explosiveness rate and 7th in passing explosiveness rate.

They also allow a lot of negative plays, ranking 95th in stuff rate (allowing a tackle at or behind the line on 23% of runs — much higher even than Ohio State’s 18% last season) and 80th in havoc rate allowed. They’re dead last in the country in fumbles lost with nine, but that’s not exactly a predictive stat, so I wouldn’t count on that against Ohio State. In terms of per-play efficiency, they rank 57th in rushing efficiency and 46th in passing efficiency, running on 71.6% of standard down (27th-most in the country). They often have far to go on third downs, ranking 105th and averaging 7.9 yards to go. They are decent in the red zone, getting touchdowns on 58% of red zone trips.

So that makes for an exciting offense — OK in per-play efficiency, but both allow a lot of negative plays and create a lot of explosive plays! Let’s look at a couple of individual players.

First, here is how Adrian Martinez compares to Justin Fields in terms of passing expected points added (EPA) success rate (x axis) and average EPA (y axis). EPA success rate essentially captures how efficient a player was on average, relative to expectations based on down, distance, and field position. It’s like a super-charged version of success rate. Average EPA captures the magnitude of successful plays too, so it also measures explosiveness.

In the chart above, the darker gray around the trend line captures the 95% confidence interval of what average EPA is expected to be based on a given EPA success rate. So a point way above the gray means that the player is more explosive (and probably has fewer way negative plays) than you’d expect based on their success rate. That’s the case for Adrian Martinez. His overall success rate isn’t so hot at 43.9%, but his average EPA is higher than you’d expect to. So we should watch for big passing plays even if he may be inconsistent.

Justin Fields on the other hand, is very efficient, and within the CI for average EPA based on his high success rate. In fact, he’s currently 7th in the country in passing EPA success rate.

This chart looks at Nebraska’s receivers in the same way. Notably, I was surprised that only running back Maurice Washington, who has 149 receiving yards on eight catches, ranks far above the 95% confidence interval. J.D. Spielman is pretty efficient, however — definitely their most efficient receiver.

And here are running backs, here who can see that Maurice Washington is also more explosive than you would expect given his success rate — he’s about the same as Dobbins, but less efficient.

While you can never discount the value of a running quarterback — especially against a defense that hasn’t really faced a player like that yet this year — Adrian Martinez has been less explosive than expected so far.

---

So overall this seems like a really interesting game. They’ve got a few players that should be legitimate threats to a Buckeye defense that has performed very well so far, but also hasn’t faced an offense that is this explosive yet. On the flipside, Nebraska has allowed a ton of havoc plays, and Ohio State ranks 8th overall in creating havoc plays.

Defensively Nebraska is better than I expected but still worse than either Indiana or Cincinnati — but they also create a ton of tackles for loss. And in a tough road environment, that could make things very interesting.

I think the combination of the potential for explosive plays from Nebraska’s offense + both teams’ potential for havoc plays mean that there is a slightly wider distribution of possible outcomes in this one, but one that the Buckeyes probably win most of the time.