There is no shortage of questions facing the 2023 USC defense following a difficult first season on that side of the ball under Lincoln Riley.

Hamstrung by a lack of both top-end talent and depth last year, the unit hopes to be much improved following an influx of intriguing reinforcements via both the high school recruiting and transfer classes.

If USC’s ambitions of making a run at the College Football Playoff are to be actualized, that improvement will be mandatory. The good news is that it can be assumed fairly easily that this group’s floor should be higher than last year’s, given just how low that bar was set.

Despite the wave of fresh talent that figures to feature prominently on the defensive side, the Trojans’ biggest difference-maker there will likely be a player preparing for his third season in the Cardinal and Gold. Safety Calen Bullock has been a force on the back end of USC’s defense from the moment he began to take serious reps early in his freshman year. As a sophomore last season, Bullock fully took control of a starting safety spot and manned it confidently for the duration of the year.

The young safety had an excellent season for the team, serving as its biggest defensive difference maker alongside Tuli Tuipulotu en route to a first- team All-American nod from PFF. Bullock secured a well-above-average 82.5 season grade from PFF -- the top score of any Pac-12 safety last year, as he racked up 48 tackles, 5 interceptions and 5 passes broken up.

His role at the very back of USC’s defense will remain critically important, and a continuation of the upward trajectory of his play could stand to make him the focal point of a unit that desperately needs his playmaking ability.

Let's take a closer look at what makes Bullock not only a key for the Trojans this year but one of the most intriguing safeties in college football ...

The nature of the safety position in college football has changed significantly over the past decade or so. Gone are the days of clear distinction between free safeties and strong safeties as designated positions with varied skill sets and responsibilities.

For the most part, the modern college game prioritizes flexibility at the position, emphasizing the value of safeties who are capable of handling the whole range of duties that might be needed on the back end. Most teams rotate their safeties between roles fairly evenly -- in fact, the Trojans’ previous coaching staff had made a point of how minimally they saw the difference between the two starting safety spots on the defense.

When watching tape of USC’s 2022 defense, however, it becomes abundantly clear that this coaching staff understands Bullock for what he is -- a true, top-flight free safety. Though Bullock’s skill set is versatile and allows him to be a difference-maker in split-field and box alignments, the traits that make him unique and irreplaceable are evident when he’s asked to roam the back end of the defense as a centerfielder. What sets the safety apart are his range, length and patience, skills that allow him to patrol the deep area of the field expertly as he diagnoses and reacts to plays unfolding before him.

Standing at a wiry 6-foot-3 with long arms, Bullock’s lengthy frame allows him to maximize his chances to make plays on the football and to fight for the ball at the catch point with anyone. What’s most impressive is the way he’s able to move that frame across the football field, with top level acceleration and feet quick enough to redirect with ease. Those traits are what amount to the skill we describe as “range”, the ability for a player to cover grass with ease in order to affect plays developing many yards away from them. It’s perhaps the most desirable trait to look for in a single-high safety, and Bullock is likely the best at it of any safety in college football today.

His ability to eat up ground as he picks up receivers, pursues ball-carriers and hawks the thrown football is arguably second to none. Even though he’s often aligned over 15 yards away from the line of scrimmage at the snap, Bullock’s range makes him a factor to produce a stop on any given play, even if it’s a screen or run to the far side of the field.

Most importantly, he’s rarely if ever beaten when directly challenged on a deep route, providing the kind of dependable roof all defenses covet on the back end. Though Bullock is plenty capable of handling the responsibilities of a box safety and will be asked to do that from time to time in Alex Grinch’s scheme, a significant majority of his snaps are spent playing the kind of single-high role Earl Thomas once played for the Seattle Seahawks. Stylistically, he best compares to former Ohio State free safety Malik Hooker, another long, rangy player on the back end who excelled at making plays on the ball and covering every blade of grass on the field.

In reviewing Bullock’s film, I’ve broken down a collection of his tape sorted by the strengths and weaknesses that are apparent from play to play, watching a couple full games of All-22 film (a broader view than the TV broadcast that shows all 22 players on the field at all times) from last season: USC at Stanford and USC at UCLA.

I watched and charted every snap of Bullock’s from those two contests and I’ve included all of his notable plays -- positive or negative -- in this review. It’s a good pairing of film with one coming from the early season and another almost at the very end, allowing for a comparison of his play across those points in time. I’ve also included a number of plays from other games this season that highlight his strengths or weaknesses, but unfortunately I didn’t have the All-22 to work with so you’ll have to settle for the broadcast angles from clips on Twitter (I refuse to call it anything else).

Strengths

-Range: As touched upon earlier, Bullock’s ranginess is his greatest asset on the football field. Once he’s identified where the football is going and pulls the trigger, he moves like he’s been fired from a barrel. His rapid acceleration, clean footwork and length of stride allow him to cover ground with ease. His general awareness for both space and his own footwork plays a part here as well, helping him instantaneously determine the optimal route to the football as he leaves no wasted steps on the field.

It’s obvious very quickly that Bullock has identified where this play is going just fractions of a second after the snap. Even though he’s set up in a 2-high alignment, Bullock is supposed to be a box-safety manning the hook zone underneath, so he plants his foot in the ground and fires toward the direction of the run almost simultaneously with the back himself.

As he’s working downhill, he identifies the nature of the run and takes a handful of scraping steps laterally to widen out, allowing him to contain the edge. The speed with which he’s gotten to the line of scrimmage busts UCLA’s intended design, leaving him completely unblocked and able to wrangle Zach Charbonnet down without allowing a single yard.

Bullock is spying the quarterback on this play and fires downhill instantaneously to get into proper position. He closes the ground rapidly and sees that Dorian Thompson-Robinson is still waiting in the pocket before firing his feet once more in a beeline straight at the quarterback. Bullock is directly in DTR’s line of sight at this point and closing fast, so the Bruins signal-caller turns to the right to find a throwing lane and gets the ball out of his hands as quickly as possible to the waiting curl.

In his urgency, he fails to notice a waiting Mekhi Blackmon, who pounces for the interception. There’s hardly any pocket pressure to speak of on this play -- you can see the quarterback’s internal clock speed up the moment he recognizes Bullock closing in on him as he reads from left to right.

The Trojans decided to send a blitz at Stanford QB Tanner McKee, leaving Bullock as the lone deep safety while all other remaining defenders pick up a man in coverage. Jaylin Smith completely whiffs on his assignment, allowing the tight end to cross the middle of the field totally unchecked. As the free safety, Bullock realizes what’s gone wrong before the quarterback has wound up for the throw, adjusting his footwork so he can begin working back over the middle of the field to stay over the open tight end. Bullock is almost 10 yards away from him, but he’s already planted his foot in the ground and begun to drive downhill at the moment McKee lets it go.

Notice the angle taken here by the young safety; instead of firing himself at the catch point like many defensive backs would, he’s taken the trajectory that leads him to the exact spot the tight end turns into after securing the catch, a few yards away from where the throw was aimed. Paired with his impressive closing acceleration, that pursuit angle allows Bullock to stop the play almost instantly after the catch. If he had gotten there just a second later, there’s a solid chance this play ends up a touchdown.

This one is a simply jaw-dropping piece of football and perhaps the best example of Bullock’s range on film. The ball is snapped on one hash and Bullock is lined up on the other before starting his single-high drop. He gets his eyes on the deep-crossing No. 2 receiver as he gathers depth and accordingly begins to mirror his movement across the middle of the field, eliminating the possibility of a throw there. Bullock then notices the soft post-corner route developing outside and begins to haul himself at full speed to get himself just under it.

Cal QB Jack Plummer throws a ball that hangs in the air just a beat too long, and that’s all it takes for Bullock to snatch the ball out of the air all the way on the far sideline from where he started. Note the speed with which he covers the ground and his feel for how the route progression is playing out.

Similar to the last play, Bullock flashes his uncanny ability to play the football all the way to the sideline even from a deep-middle alignment. Beginning his drop between the hashes, he reads the Colorado quarterback’s eyes as he follows the deep corner route from the slot receiver and he immediately begins to mirror the movement himself.

Bullock is yards inside of the slot receiver at the point of the break and the ball ends up all the way at the sideline -- the odds of a safety getting to that throw in time should be minimal. However, Bullock simply closes ground too fast, easily outpacing the receiver once he begins his burst toward the football while cutting him off from over the top to snag it for himself. Both his natural acceleration and his precise understanding of footwork and angles allow him to completely take over this rep.