Maryland football switches to 4-3 defense in 2015: Will it help Terps stop the run?

Maryland head football coach Randy Edsall was at a podium in Chicago last week for the Big Ten's annual media days. A season now past since his program's switch from the ACC, a reporter asked Edsall what his first Big Ten slate taught him about the league. Edsall's answer was the same one he's given in the past when asked about his strategy on offense, defense or the recruiting trail.

"Well," Edsall said. "I think that we found out that it was really a lineman league. That you had to be able to win in the trenches if you were going to be successful, week in, week out, year in, and year out."

Edsall is right. The Big Ten is a lineman's league, both in terms of its best talent and its raw roster apportionment. Last season, just two teams – Maryland and Wisconsin – used base 3-4 defensive schemes, with three down linemen and four linebackers. Everybody else typically had four defenders starting plays with their hands on the turf. (Oddball Purdue deployed a sort-of, kind-of 3-4 look, but used multiple schemes.)

Now Maryland's joining the herd. Defensive coordinator Brian Stewart and his 3-4 alignment are both gone. Former Maryland linebackers coach Keith Dudzinski is in at coordinator, working with Edsall to install a 4-3 base. College teams have about a million different packages they use on defense, but Maryland's shift leaves Dave Aranda's Wisconsin unit as the lone classic 3-4 defense in what might be college football's meatiest conference.

Everyone involved has been transparent about why Maryland's making this switch. The Terps were regularly gashed in the running game last year, and now they've lost seven front-seven members. The Big Ten is essentially a cattle drive up front, with some of the most abjectly terrifying linemen in the sport set to face Maryland this season: Ohio State's Joey Bosa, Michigan State's Shilique Calhoun and Penn State's Anthony Zettel are just a few. Those are all first-round NFL picks, and they're each supported by three other down linemen on just about every single play.

In the Big Ten, how much good does a 4-3 defense actually do? It's hard to say, but numbers can help answer.

The conference's 3-4 defenses (including Purdue, which is admittedly an imperfect example) are in bold. You've got Wisconsin there, being good, which Wisconsin typically is. The Badgers used to have J.J. Watt. They've been in the top 25 in rush yards allowed per game for each of the last three years. They also recruit way better than the rest of the Midwest.

Then you've got Maryland and Purdue, lagging pretty close to the bottom of the conference. It's the same deal if you go back to 2013, before Maryland went B1G: Wisconsin was No. 2 in the league in rush defense (by average yards per carry), and Purdue was No. 10 in what was then a 12-team league. The year before that, Wisconsin was No. 5 and Purdue No. 9. It's a similar enough pattern, born from Wisconsin recruiting enough talent to make it work and Purdue not.

Here are the combined rushing statistics of the conference's four- and three-down linemen defenses from 2014:

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Advanced metrics lead us to roughly the same conclusions. Maryland's 3-4 defense in 2014 placed 77th nationally in S&P+, a measure based on the success rate of every rush attempt, explosiveness and field position. The Terrapins ranked 90th in adjusted line yards (more on what that exactly is here, but it essentially measures a line's effectiveness) and 100th in power success rate, allowing opponents to succeed on third or fourth downs with two or less yards to go on an astonishing 73.5% of attempts.

Wisconsin was 29th in S&P+ with its 3-4, and Purdue was 82nd. A 3-4 stops the run if your players are really good, and it leaks if they aren't. Nothing earth-shattering about it.

But, then, look at the best rush defenses in the Big Ten and nationally. In rushing S&P+ Penn State ranked No. 5 in the country last year. Michigan was No. 10. Michigan State was No. 11. Ohio State was No. 31. Iowa was No. 45. Northwestern was No. 47. That's six top-50 defenses. All of them were based in a 4-3 set.

Looking up at the tippy top of college football, now, the 10 best rush defenses by S&P+ were Alabama, Clemson, Ole Miss, Stanford, Penn State, TCU, Air Force, Arkansas, Virginia and Michigan. Out of those 10 teams, two (Stanford and Air Force) played reasonably ordinary 3-4 schemes. Alabama played a 3-4 at heart, but the Tide have such obnoxious playing and coaching talent that they mixed alignments seamlessly. The other seven top-10 rush defenses used four down linemen in their base defenses.

(Small sample size concerns here are fair here. It's also fair to point out that 4-3 defenses are a majority in college football in general, if not quite by the margin between the best defenses and the rest of them. But S&P+ is an opponent-adjusted stat, so it's not poisoned by strength-of-schedule differences. It's also clear that the majority of the best rush defenses in college football like to play with four linemen.)

In all of this, I've barely mentioned Maryland's unique personnel situation. It's a bit of a wonder that Maryland's rushing defense was so thoroughly mediocre in 2014, given that the Terps had an all-seniors front seven, plus excellent sophomore linebacker Yannick Ngakoue. It doesn't reflect well on Maryland's coaching that the Terps couldn't stop teams on the ground with the skill they put on the field.

But this transition will probably help. Ngakoue and Jesse Aniebonam should be effective with their heads down. Tackles Quinton Jefferson, David Shaw and Kingsley Opara are all interesting players, but they're certainly better off paired up than any would be holding down a nose tackle job on his own. Maryland's secondary figures to be really good this year, and Will Likely, Sean Davis, Anthony Nixon and A.J. Hendy probably won't need the help an extra linebacker would provide in coverage.

For the players Maryland has, a 4-3 defense fits. Add the clear statistical trend of 4-3 defenses plugging up running holes, and Maryland should be a lot stingier there in 2015. That's just one piece of a broader puzzle, but it's a foundation the Terrapins absolutely had to have.