Not much was expected of Purdue’s defense last season.

Purdue had a new coordinator leading an entirely rebuilt defensive coaching staff and was coming off a woefully inconsistent Covid-shortened season in which the defense seemed to get worse each week.

But the 2021 Boilermakers, led by co-coordinator and play-caller Brad Lambert, far exceeded the low expectations, carrying Purdue early in the season when it was still searching for consistent offense, then coming up with game-changing plays late in the year that allowed wins to pile up.

Now, Purdue will get a whole new set of questions. The biggest: Can new play-caller Ron English, who takes over in those duties after Lambert departed for Wake Forest, keep up the defensive momentum? Can the Boilermakers replace the productivity of D-end George Karlaftis, who left a season early to become a first-round NFL Draft pick? Are there playmakers?

If Purdue is to match last season — the Boilermakers ranked 7th in the Big Ten, allowing 22.4 points per game, and they were 8th in yards allowed at 366.5 per game — it’ll need to find positive answers.

Let’s compare the Boilermakers’ defense from last season to this:

Pressuring the QB: Worse

Karlaftis.

The former All-America end is going to be difficult, if not downright impossible, to replace. Granted, Karlaftis didn’t have incredible numbers in ’21, only 5 sacks, but his impact was far greater. He was one of the nation’s leaders in quarterback pressures, with his hassling of the opposition leading to negative plays for the offense. It also helped to open up others to make plays.

Now, with Karlaftis departed, Purdue must hope that the collective can continue to produce.

It’ll be a challenge. Purdue not only must replace the impact of Karlaftis, but of opposite end DeMarcus Mitchell. Maybe junior Kydran Jenkins, who had 5 sacks as a part-time starter last year, can be an answer. He’ll compete with newcomer Scotty Humpich, a transfer from Murray State. It’s likely both will play at what is an incredibly important hybrid end/linebacker position. Veteran Jack Sullivan is likely to fill in at Karlaftis’ spot, as he’s done a few times the last couple seasons, and with success, like in Purdue’s Music City Bowl victory over Tennessee. Then, he had 4 tackles, 1.5 for loss, and a sack. Highly regarded freshman end Nic Caraway might be ready to play from Day 1, as well.

The Boilermakers love the interior of their defensive line, led by starters Lawrence Johnson and Branson Deen, feeling it might be the deepest unit not only on the defense but the entire team. The duo combined for 5 sacks last season, including 4 from Deen.

Maybe Purdue can get pressure from linebacker/safety Jalen Graham. One of the defense’s biggest playmakers — maybe the only known one right now — the 6-3, 220-pounder could be unleashed to get after the QB more frequently this season after having just 1 sack last.

Run defense: Better

Purdue has room for improvement in its rush defense, which seems a must if the Boilermakers are to take another step forward in the Big Ten West.

The Boilermakers ranked third-to-last in the Big Ten in rushing yardage allowed, giving up 157.8 per game. But the ranking might not be as bad as it sounds; they were only 11 yards per game from moving all the way up to 7th in the league. Maybe they can actually get there this season.

Purdue has talent along its defensive line, particularly on the interior, with Johnson and Deen, along with Penn State transfer Cole Brevard and returnees Damarjhe Lewis and PrinceJames Boyd Jr. Although Purdue’s linebackers — expected starters Kieren Douglas and Semisi Fakasiieiki — have deficiencies in space, they’ve been solid run-stoppers between the tackles. Add in that the Boilermakers have size on the perimeter in cornerbacks Cory Trice and Jabari Brown, and there’s reason to think Purdue could be improved.

But the Boilermakers will be pushed in the West, particularly in matchups vs. big, physical teams like Wisconsin and Minnesota that have proven to be difficult over the years.

Pass defense: Better

Almost no one saw Purdue’s pass defense in 2021 coming. The Boilermakers allowed only 208.7 yards per game through the air, the 5th-best mark in the Big Ten, and they had 13 interceptions, the 4th-highest total in the league.

It was great. And it performed largely without the services of Trice, the Boilermakers’ best cornerback, who injured his ankle early in the year only to tear an ACL on the eve of his return. But Brown, who had transferred from Kentucky, was great as a spot starter in Trice’s place. The pair, if they stay healthy, could turn into one of the best duos in the Big Ten, certainly one of the biggest and most physical.

For the first time in years, there might be depth at cornerback, as well, with transfers Reece Taylor (from Indiana), Tee Denson (Kansas State) and Bryce Hampton (Adams College).

At safety, Purdue was stung by the late transfer departure of Marvin Grant, who had been set to return as Purdue’s leader in tackles (74) but instead will play at Kansas. It leaves veteran Cam Allen, who had a team-high 4 picks last season, and Chris Jefferson, who played mainly as the nickel back in his first season after transferring. Maybe Antonio Stevens, who suffered a devastating knee injury a couple years ago, could find his way into the rotation.

Purdue would like the secondary to be one of its strengths, and it seems likely to be so. But if the defense can get pressure in the front, even without Karlaftis, then the back half of the D seems poised to not only be solid, but potentially great.

Special teams: Better

Purdue’s punting has been … questionable … for years now, and 2021 was no different.

The Boilermakers are searching for consistency. They think they can get it from sophomore Jack Ansell, who showed enough as a true freshman to make Jeff Brohm and new special teams coach Karl Maslowski at least feel like they’re heading in the right direction.

The Boilermakers ranked last in the Big Ten last season in net punting, averaging only 36.7 per attempt.

Overall: Even

Purdue has good depth on the interior of its defensive line and in the secondary, but it doesn’t have Karlaftis, nor does it have a wealth of known playmakers, at least outside of Graham.

Could others develop? Yes. And Purdue will need that, most likely from an edge rusher — any one of the options would do — and at cornerback. Maybe a healthy Trice can become one of the best defenders in the Big Ten.

But if those things don’t happen, it could be a long season defensively for the Boilermakers.