The Big Ten is known for its defenses, so it was a little surprising to see no B1G squads in PFF’s top 10 list. It was just 2 years ago that the B1G had 5 of the top 12 in total defense.

Does PFF have a point? Time will tell. Here is the biggest concern I have with every B1G defense.

Illinois: The secondary is one of the worst in college football

According to PFF, the Illini’s outside corners were the 4th-worst amongst Power 5 teams in expected points added per target. And to top that off, 4-year starter Nate Hobbs didn’t return. The good news is that the B1G West is so weak in terms of passing attacks (is anyone scared of Northwestern, Iowa or Nebraska?) that Illinois should be able to mask some of it. New defensive coordinator Ryan Walters survived 3 regimes at Missouri, so obviously he knows what he’s doing.

Indiana: Replacing DC Kane Womack

As Indiana has built up its program, it is dealing with the realities the big boys face many years: Other teams want your assistants. For the second straight season, the Hoosiers lost a coordinator to a head coaching job. Kane Womack is now at South Alabama, but his defensive system remains, as do key players like Tiawan Mullen, Micah McFadden, Reese Taylor and Jaylin Williams. Indiana isn’t really strong up front, but it makes up for it in the back 7.

Iowa: Turnover up front

Every year, it seems Iowa is replacing 3 starters up front, including Big Ten Defensive Player of the Year Daviyon Nixon. That’s no different in 2021, as only Zach VanValkenburg is back. Not to worry, though, as Phil Parker’s defense always seems to reload. The secondary will be excellent, so really, this unit’s success will come down to whether Iowa can get the same sort of production up front. Can they get a little more pressure on the QB?

Maryland: Production hasn’t caught up to talent

Maryland is loading up on high-level defensive recruits. Its top 5 recruits in the 2021 class are all 4-star or 5-star guys on that side of the ball. But as far as the here-and-now is concerned, who are the impact players? Safety Nick Cross has shown why Alabama and Ohio State wanted him, but aside from him, the Terrapins are just lacking in star power on that side of the ball.

Michigan: Growing pains in new scheme

The Wolverines had to make a change — such is life after a 2-4 season — but that comes with growing pains. Don Brown’s defense had its flaws, especially against the premier programs, but don’t forget that the Wolverines were a top-11 defense nationally from 2014-19 until falling off last season. Can new defensive coordinator Mike Macdonald figure out how to utilize the skill sets of former 5-star recruit Chris Hinton and former 4-star recruit Mazi Smith in his 3-4 scheme? Will Michigan chill out with the blitzing to avoid constantly getting burned on the back end for big plays? We’ll see how Macdonald adjusts the defense.

Michigan State: Depleted secondary because of transfers

The Spartans finished the spring with only one scholarship corner on the roster. While they have since added transfers from Alabama, Florida, Louisville and Arizona, the lack of continuity could be a bit problematic. Maybe those guys will be an upgrade, though, as Michigan State’s secondary wasn’t very good in 2020.

Minnesota: Atrocious run defense

The Golden Gophers allowed 6.3 yards per rush, which was 124th out of 127 teams (and the worst among Power 5 teams). While shutting down an offense’s passing attack is usually a recipe for success, you can’t win if your run defense is a turnstile. Minnesota added transfers from Clemson, NC State and Notre Dame to help aid the defensive line and hopefully shore up that abysmal run defense.

Nebraska: Added pressure because of subpar offense

Nebraska’s defense should be one of the Big Ten’s best in 2021. There isn’t too much to nitpick here, even with Will Honas suffering a knee injury during spring and missing all of 2021. The secondary is experienced with Cam Taylor-Britt and Deontai Williams, and JoJo Domann is one of the conference’s best all-around defenders. But can the defense go out and win games? That’s asking a lot for a unit that wasn’t very goo when Frost took over 3 years ago and deserves a lot of praise.

Northwestern: Losing Greg Newsome

Subtracting a first-round corner from any defense poses challenges, even Alabama or Ohio State. So how will the Wildcats be without Newsome, who according to PFF allowed just 93 yards on 34 targets? Safety Brandon Joseph was an All-American, and corners A.J. Hampton and Cameron Mitchell seem ready to pick up the slack, but having a shutdown corner is a luxury that you don’t always realize until it’s gone. Like how many guys can hold down David Bell like Newsome did? Northwestern played pretty well without Newsome once he got hurt in the Big Ten Championship, but we’ll see how it affects the Wildcats over a greater sample size.

Ohio State: Pass defense needs to be fixed

It was unusual to see the Buckeyes struggle in the secondary last season. The Buckeyes far and away had the worst pass defense in the Big Ten, allowing 304 passing yards per game. Granted, they played Clemson and Alabama to close the season, but even a Buckeyes fan would acknowledge that it was a problem before then, like when Michael Penix Jr. nearly threw for 500 yards. The onus is on guys like Sevyn Banks, Cameron Brown, Lathan Ransom and Josh Proctor to get Ohio State back to the level it has been at in previous years.

Penn State: New starters up front

It’s honestly hard to find too much with Penn State’s defense. Despite the down season, the Nittany Lions were top 4 in the Big Ten in total defense, rush defense and pass defense. The secondary returns 3 of 4 starters, and there is a lot of talent at linebacker. So, let’s go up front, where Penn State must replace first-round pick Jayson Oweh and Shaka Toney. PJ Mustipher is the only starter back on the defensive line, as Penn State will rely on transfers from Duke and Temple.

Purdue: Weak back 7

Brad Lambert takes over as defensive coordinator after leading Marshall to the No. 1 defense in FBS. With edge rusher George Karlaftis anchoring the defensive line, Purdue is set. But the linebacking corps and secondary will likely be among the worst in the Big Ten. The Boilermakers were 4th in the B1G in rush defense last season in allowing only 3.4 yards per attempt, but they were next to last in pass defense at 7.9 yards per attempt.

Rutgers: Oversized expectations

Rutgers is definitely on the right track, so much so that it’s hard to nitpick. After having one of the worst defenses in FBS in 2019, the Scarlet Knights made a huge jump into the middle of the pack in 2020. Greg Schiano is a former defensive coordinator, and he has this group ready to take another step forward with 10 starters back, including Defensive Player of the Year candidate Olakunle Fatukasi. And maybe that’s the biggest concern; this group got a taste of success last season and is expected to challenge for a bowl game. How will they handle those expectations?

Wisconsin: Inexperience up front

Keeanu Benton is the only returning starter up front in Wisconsin’s 3-4 defense. Matt Henningsen, who has started in the past, and Isaiah Mullens take over the end spots. Behind them, though, there isn’t much of anyone who has game experience. Wisconsin’s linebacking core should be good, as usual, and same for the secondary, so this feels like nitpicking a very good defense. But it is a concern, nonetheless.