Fittingly, it’s been a defensive-dominated year in the B1G.

Eight defensive units rank in the top 31 in scoring while only one B1G offense (Ohio State) ranks in the top 31 in scoring. Go figure.

Schools like Illinois and Minnesota are both in the top 31 but aren’t even in the top half of the B1G in the defensive power rankings at the midway point of the season. That says a lot.

So who is No. 1 at the midway point of the season?

14. Purdue

Losing Ja’Whaun Bentley hurt, but this was a unit that was struggling long before its leading tackler went down. Here’s a weird stat. The Boilers have allowed at least 35 points to every opponent this year, with the exception of Michigan State.

13. Maryland

There’s no way the Terps should be struggling as much as they are defensively. Yannick Ngakoue has had an All-Big Ten season, but Maryland hasn’t gotten much pressure on quarterbacks, which has made it easier to take advantage of the Terps secondary. It doesn’t appear Keith Dudzinski’s 4-3 defense is working.

12. Indiana

There wasn’t much of anything the Hoosiers could stop in non-conference play. Zack Shaw and Nick Mangieri have been solid, but the consistency has been hard to find for Kevin Wilson’s group.

11. Rutgers

The loss of Darius Hamilton was a big one. Without him, the Scarlet Knights are averaging less than two sacks per game and are ranked 115th against the pass.

10. Nebraska

The Huskers have actually been decent in B1G play against two capable offenses in Illinois and Wisconsin. So what’s holding the Huskers back? They rank dead last in FBS in passing yards allowed. Woof.

9. Illinois

Dawuane Smoot and Clayton Fejedelem have emerged as playmakers for an Illinois defense that was lacking them at the start of the season. Illini’s run defense needs work but the coverage in the passing game has actually been serviceable most of the season.

8. Minnesota

If this unit was healthy, it would be much higher on this list. Still, give Jerry Kill’s group credit for still being one of the nation’s better scoring defenses without Briean Boddy-Calhoun and Damarius Travis.

7. Michigan State

Speaking of injury-depleted units, Michigan State is as banged up as anybody. The Spartans are playing bend-don’t-break defense right now. As long as Shilique Calhoun and Riley Bullough are on the field, though, MSU has a couple of game-changers.

6. Iowa

Again, with a healthy Drew Ott, this unit is much higher. Desmond King has been as good as any corner in the country while the likes of Nate Meier and Cole Fisher have been underrated catalysts for Kirk Ferentz’s defense.

5. Ohio State

Early on, the Buckeyes were bailing out the offense. In B1G play, it’s been the other way around. Mobile quarterbacks have been the downfall for OSU so far. Lucky for the Buckeyes, the only mobile threat left on the schedule is Jake Rudock. And some might argue that.

4. Penn State

Carl Nassib might be 2015’s version of J.J. Watt. The former walk-on leads the nation in sacks and has clearly found a home playing regularly with the likes of Anthony Zettel and Austin Johnson. Since that horrific opener against Temple, the Lions have allowed less than 12 points per game. That’ll work.

3. Wisconsin

Nassib and Joe Schobert are the top two candidates for B1G Defensive Player of the Year so far. And while Schobert has stood out the most, the Badgers have been getting big efforts from their entire linebacking core. Most impressive about the Badgers is that they don’t need to force turnovers to be dominant. That will keep this group as steady as they come.

2. Northwestern

Well, if you would’ve asked me this question a week ago, No. 1 and No. 2 would’ve been flipped. Rarely is a team not the best in its conference when it’s surrendering a mere 12 points per game. Why have the Wildcats been so good without any household names? They’re seventh in the country in third-down stops and they’re the least penalized team in the B1G.

1. Michigan

You’ve been alive the last three weeks, right? You know the numbers. The Wolverines recorded three straight shutouts for the first time in 35 years, they have 41 straight possessions without allowing a score and they rank first in America allowing a teeny, tiny 6.3 points per game. Jourdan Lewis is having an All-American season at corner, Jabrill Peppers is making all the necessary plays at safety and Joe Bolden is anchoring the nation’s No. 3 run defense. If Michigan’s dominance continues against Michigan State, break out the record books.