Veteran defensive end Jamil Muhammad said going through practice this spring under new defensive coordinator D'Anton Lynn was "like night and day" for the unit.

Defensive back Prophet Brown added that this Trojans defense is "completely different" from the one that stumbled for most of the last two years under the previous regime.

"We've brought in a lot of new players as well. It's not just all scheme. So, I feel like the players are really buying in and stepping up and playing for one another, and we're being put in position to make these plays and have the freedom to go out there and play fast," Brown said.

But in what specific ways have the Trojans transformed on the defensive side and what have we truly learned about the scheme Lynn will employ this season?

A lot, actually, despite media not being able to watch any meaningful practice reps and the spring game being a limited showcase by nature -- albeit one in which Lynn's defense forced five turnovers and won the day.

In fact, we had so many thoughts on the defense coming off the game Saturday that instead of our typical all-encompassing First-and-10 breakdown we had to split the two sides of the ball up.

Here, we delve deep into the Trojans' new defense with our takeaways and projections based on what we've learned to this point.

Despite the abundance of new starters on the offensive side of the ball, the attention of the viewing audience for this spring game was always going to be fixated on the Trojans’ revamped defense.

D’Anton Lynn’s unit performed quite well across the board in its first public showing, forcing four interceptions (plus a fifth turnover on a backward pitch snatched out of the air) while consistently challenging the offense. The fundamental changes to the scheme and philosophy of the defense from those of Alex Grinch’s tumultuous tenure were clear to see, despite the limited nature of what was being run on the field.

We’ve heard talk all offseason about how the team was going to move away from the “speed defense” of the past two years and instead emphasize size and physicality at the point of attack. The visible aspect of that change has been evident all spring, with muscle mass gained all across the roster as well as the addition of longer, stronger body types. However, a full philosophical transformation of the defense was always going to require more, including tangible structural changes and an adaptation of how individual players were coached to play their roles in order to be effective.

All of that showed itself in USC's spring game, particularly with regard to the base structure of the defense. Grinch almost exclusively played his guys in a 4-2-5 alignment, with all players on the defensive front single-gapping from down to down and heavily relying on pre= and post-snap movement to create opportunities. His defense emphasized “havoc plays” by selling out to force early penetration in order to push the offense into making mistakes with the football. It’s a high-risk, high-reward strategy, and one that USC simply did not have the defensive personnel -- or coaching -- to pull off successfully.

Lynn’s defense is quite different, based in two-gapping 3-4 personnel with a healthy dose of the 4-2-5 nickel alignment mixed in. That defensive structure is derived from the most popular and successful family of defenses in both the NFL and CFB today, borne out of the Baltimore Ravens/University of Michigan defensive coaching tree that Lynn himself is an extension of from his time as the Ravens' safeties coach in 2021-22.

When noting what makes this style of defensive scheme unique, the first point is the emphasis on stifling opposing run games on early downs. This is where the 3-4 base personnel makes a difference, with larger body types holding down the middle of the formation and a total of at least five and often six players up at the line of scrimmage. It was difficult to really draw conclusions about the run game on Saturday given the limitation of contact -- the Trojans were in "thud" mode rather than full tackling for most of the game -- but it appeared as though USC’s interior defensive linemen struggled to handle their two-gap responsibilities against the run, often getting blown straight off the ball to produce sizable lanes. Bear Alexander’s return to the lineup should make a big difference there, but the Trojans will almost certainly need to add more mass and power at the position via the portal.