The second part of our 2017 Summer Guide is position previews. For each position, we'll outline who's returning, who's gone and what the big question facing the unit is before finishing up with our projected depth chart for each position.

Next up, we have the defensive line.

Overview

Returning starters (career starts): DT Tyler Lancaster (25) DT Jordan Thompson (12) DE Xavier Washington (8, suspended indefinitely)

Key losses: Ifeadi Odenigbo, C.J. Robbins, Joseph Jones

Other returners: DE Joe Gaziano (R-So.) DE Trent Goens (R-So.) DT Alex Miller (So.) DT Fred Wyatt (R-Jr.)

Incoming Freshmen: Joe Spivak, Sam Miller, Trevor Kent, Earnest Brown IV (Fr.); Mark Gooden, Jake Saunders, Tommy Carnifax (R-Fr.)

Northwestern’s secondary should continue to improve and improve a pass defense that struggled at times last year. Uncertainty looms up front, however, as the Wildcats could lose three of their top four defensive lineman from last year pending the outcome of Xavier Washington’s suspension. A younger group returns on the defensive line, especially on the edge.

The Wildcats may lack experience at defensive end, but they don’t lack talent. Coach Fitz has devoted a lot of his recruiting energy to snagging commitments from highly-rated defensive ends like Joe Gaziano, Trevor Kent, and Earnest Brown IV. Gaziano returns after a redshirt freshman campaign that saw flashes of solid playmaking ability. Either Trent Goens, who saw time in nine games last year, or Tommy Carnifax will be the other starter if Washington is unable to play. Keep an eye on incoming freshman Brown as well. The four-star defensive end was Fitz’s top recruit in the class of 2017 has the size (6’5”, 240 pounds) and the pedigree to make an impact right away. Same goes for Trevor Kent, another top recruit from the class.

Anchoring the tackle spots are Jordan Thompson and Tyler Lancaster, both of whom are returning starters. A big part of Northwestern’s strong rush defense in 2016, the duo will be tasked with stopping the likes of Saquon Barkley and Akrum Wadley. At least they don’t have to tackle Justin Jackson. Alex Miller and Fred Wyatt have experience at tackle as well, and will see plenty of snaps.

Most Important Player

Joe Gaziano

Every defense needs playmakers up front, and with Anthony Walker Jr. and Ifeadi Odenigbo gone, a new disruptor is needed in the front seven. In backup duty last year, Gaziano managed to rank second on the team with 4.5 sacks, and registered big games (including the loudest sack of the year) against Michigan State and Pitt in the Pinstripe Bowl. One of two returning defensive ends with game experience, Gaziano is the de-facto leader of a young group of edge rushers. The top-rated player in Massachusetts in 2015 will need to make the leap from a specialist to an every-down menace if Northwestern wants to stave off regression on the defensive line.

Big Question

Who is getting to the quarterback?

With 37 combined starts, Lancaster and Thompson are more or less known entities. Both have shown the ability to make plays and occupy space on the interior. Northwestern’s edge pass rush is a larger question. Northwestern finished 91st in Adjusted Sack Rate last season, and Anthony Walker Jr., Robbins, Odenigbo take their playmaking talents and over 50% of Northwestern’s sacks to the NFL. Beyond Gaziano, the ‘Cats will look to Goens and Carnifax, highly-regarded recruits in 2015 and 2016, if Washington is suspended for the season, but don’t be surprised if Brown sees time in passing situations. Early contributions from the true freshman may be necessary if the Wildcats hope to maintain any semblance of a pass rush.

Defensive Line Depth Chart

Let’s hope Xavier Washington can play this season.