Fans are calling for defensive coordinator Aaron Henry’s job, and even media members have started questioning whether Bret Bielema should takeover play-calling duties or if a change is needed this offseason.
A common refrain from both Bielema and Henry after poor performances is the same: What are we asking players to do? Can they actually do it? Are we setting them up for success or failure?
That question cuts to the heart of the issue.
You can theorize all day about what the “optimal” defense looks like. How multiple it could be, how much it could disguise coverage, how much havoc it could create, but complexity comes with a cost. The more you ask players to process mentally, the slower they play. In a game of inches and milliseconds, that split-second of hesitation can neutralize physical ability. Illinois’ coaches have repeatedly said they need to simplify so players can play faster.
That’s what made Ryan Walters’ defense so good. He let his players attack and play free. They played to win, not to avoid losing. Walters’ Purdue tenure did not go smoothly, but you could see the difference clearly in the Illinois–Washington game: one defense flying around, another playing in sand.
Luke Altmyer said it best after facing Washington:
“Some of the best corners I’ve seen in the league through my three years being here, and they flew around. They play really fast defensively.”
That sounded a lot like a Ryan Walters defense. That sounds a lot like the 2022 Illini defense.
Aaron Henry’s defense is the opposite. It’s conservative—bend-don’t-break, limit explosives, force long drives, hope for a penalty or a mistake. That approach can work against weaker opponents. It doesn’t against top-30 offenses. It’s like last year’s Illini basketball defense: safe, predictable, and easy to scheme against.
Illinois’ soft zone gives opponents easy checkdowns and third-down conversions. Without pressure up front, quarterbacks have time, and receivers eventually separate. The current structure often boils down to give up a touchdown slowly or hope the offense screws up on their own.
If you’re going to allow touchdowns anyway, do it while creating chaos. The Ryan Walters defense gave up some big plays, but it dictated terms and generated turnovers. The Aaron Henry defense plays to prevent explosions only to engineer its own slow, controlled demolition.
Below is a screenshot of a third down that sums it up. The Washington receiver at the top left is about to catch the ball with nothing but daylight ahead for an easy first down. Far too easy.
I found this quote from Ryan Walters via 247 Sports when he was with Illinois.
You don’t have a call sheet on game day and simplifying vocabulary, is that an indication of why you’ve been so successful?
Walters: “I definitely think there’s an organic relationship between staff and players. The way we operate, if that’s got a correlation between that and us having success or not, I’m not sure. It’s just the way I’m comfortable operating and the way our players have been comfortable with that communication piece. Whether or not I’m holding a call sheet or holding it in my back pocket, I don’t know if that has anything to do with the success or lack thereof on the field.”
At the end of the day it’s about communication and execution. Can you communicate to the players what they need to do in a way that they can go out and execute the gameplan?
How Bad Has It Actually Been?
Let’s put numbers to the vibes and see where Illinois ranks among Big Ten defenses.
15th - SP+ Defense
12th - Defensive EPA
12th - Run Defense EPA
11th - Pass Defense EPA
LAST - Points Allowed Per Drive
13th - Quality Drive Allowed %
17th - Points Allowed Per Quality Drive
15th - PFF Defene Grade
10th - PFF Run Defense Grade
14th - PFF Tackling Grade
3rd - PFF Pass Rush Grade
17th - PFF Coverage Grade
14th - Scoring Defense
15th - Defensive Kford Rating
15th - FEI Defensive Rating
Let’s looks at where Illinois ranks among Big Ten teams in conference games only
LAST - Scoring Defense
17th - Total Yards Allowed Per Game
LAST - 3rd Down Conversion %
LAST - 4th Down Conversion %
LAST - Red Zone Score %
LAST - Red Zone TD %
LAST - 10+ Yard Plays Allowed
LAST - Opponent Total First Downs Per Game
LAST - Passing Yards Allowed Per Game
13th - Passing Yards Allowed Per Attempt
LAST - Completion %
16th - QB Rating Against
17th - Passes Defended Per Game
16th - Pressure %
15th - Sack %
15th - Sacks Per Game
15th - Interceptions Per Game
15th - Run Yards Allowed Per Game
13th - Yards Allowed Per Rush
13th - Run Defense Broken Tackle/Missed Tackle %
16th - Stuff %
16th - Tackles For Loss Per Game
9th - Fumbles Forced Per Game
That’s 39 defensive stats with only one above the conference average, and that’s PFF Pass Rush Grade which I know will make some people laugh.
A fair caveat: most of these stats are not opponent-adjusted. In Big Ten play, Illinois has faced the 1st, 2nd, 3rd, 6th, and 95th ranked offenses nationally in Offensive EPA. That’s a brutal stretch for any defense. Still, even with context, the film matches the data: miscommunication, blown assignments, players looking uncertain pre-snap, and few signs of cohesion. Even after opponent adjustments, Illinois still grades out as roughly the 12th–15th best defense in the conference.
The schedule gets lighter down the stretch, with games against offenses ranked 40th, 69th, 103rd, and 106th in Offensive EPA. The Illinois defense will probably improve just by facing weaker competition. The concern is that a late-season uptick could mask how fundamentally flawed this defense has been.
The Aaron Henry defense has never been good. Here’s where it has ranked in the Big Ten by EPA each season:
2023
15th - Overall Defense
12th - Run Defense
17th - Pass Defense
2024
14th - Overall Defense
16th - Run Defense
10th - Pass Defense
2025
12th - Defensive EPA
12th - Run Defense EPA
11th - Pass Defense EPA
And let’s not forget that the 2024 Illinois Pass Defense faced only one team ranked in the top 60 of passing offense.
The worry for some fans is that Illinois might play just well enough down the stretch against weaker competition for Bret Bielema to retain Aaron Henry for another season. When Illinois lost to Nebraska 20–7 in 2023, it looked like Barry Lunney Jr. might not last long either, but even that never got this bad..
And this isn’t the old Big Ten West anymore. This is the era of revenue sharing and raised expectations. This is the Josh Whitman Illini program: measured, professional, and operating in the big leagues. There’s no way he can look at the defensive product of the last three seasons and call it acceptable.
It’s time for change.
There’s nothing the Aaron Henry defense can hang its hat on. It doesn’t take anything away from an opponent. It can’t stop the run, can’t stop the pass, can’t generate pressure, and can’t get off the field.
Expectations have evolved. Illinois football has evolved. The defense has regressed.
The Good News
Illinois should beat Rutgers this weekend. Both defenses have struggled, though Rutgers’ might be worse. Expect an offensive shootout. The two teams are similar in profile, but Illinois holds small advantages across most areas. enough to give the Illini a 74% win probability.
The following sites were used for stats in this article:
Full Game Replay
I didn’t even bother taking the commercials out of this one. No one’s going to rewatch this disaster of a game anyway.
End on a high note:
Nice write up, thanks for breaking it down. Hope we can score enough down the stretch to still get to 8-9 wins