John Butler's vision for his Nebraska defense is coming together this spring, and it involves plans to be a multiple unit with more personnel packages than last season.

The days of calling Nebraska's defense a standard 3-3-5 are no more. Instead, Butler plans to create a defense that utilizes depth and has the ability to create different personnel groupings that best matches the offense it's going against.

"We probably have a pretty firm two-deep right now in terms of guys that are in the mix at different positions," Butler said Thursday during a press conference. "And when we're saying multiple, we're multiple scheme-wise, but we want to have as many personnel groupings as we can have that would then utilize our personnel, some individual players do certain things."

While being multiple with the capability of deploying different and unique personnel packages involves all three levels of the defense, it's the back end — Butler's specialty after spending 10 seasons coaching DBs in the NFL — where it could be most notable with who's on the field in certain situations.

"Some of them have played some other positions, too, which helps us, allows us maybe to play, at times, three corners on the field, or obviously three true safeties," Butler said. "So it allows us to kind of put different pieces to the puzzle together. But I would say that unit, collectively, as not only the numbers of it, but also how they've performed, has been an area I think that should be a strength for us."

Through 11 spring practices, Butler said he's liked what he's seen from a man coverage standpoint, and a certain group of players have helped strengthen that aspect of the defense.

"I think some of the additions we have in the secondary have allowed us to do that," Butler said.

Nebraska's DB room added Idaho transfer Andrew Marshall as well as Georgia safety Justyn Rhett and Southern Illinois transfer Jamir Conn. Conn hasn't practiced this spring as he rehabs an injury.

With the spring transfer window now open until April 25, there will likely be movement on Nebraska's roster. And with a loaded DB room, it won't be surprising if there are departures.

"We could start six different guys at corner right now. We could start four or five different guys at safeties," head coach Matt Rhule said Saturday. "So, one of them might say, well, if I'm not the starter, I'm going in the portal. So that might change in the next week or so, but for the most part, great players love competition."

One DB who will be part of the plans for the fall is Malcolm Hartzog.

Hartzog is a veteran player who's played in 36 career games with 30 starts. A solid tackler for the most part, he's racked up 107 career stops — 71 of which are solos — and seven interceptions, four of which came last season.

Putting players in positions to be successful is what Butler is interested in most. That's sparked a position change for Hartzog. After spending last season as an outside corner and free safety, Hartzog has been moved to nickelback, where he can play closer to the line of scrimmage instead of being asked to cover bigger receivers down the field in one-on-one situations.

The move to nickel won't be a huge change for Hartzog. In former DC Tony White's scheme, the field safety has nickel responsibilities at times in the five-DB setup.

"I think of him as like a true nickel that can come down and play man on two," Rhule said of Hartzog this spring. "And when he's out there, you don't have to play, oh, let's put a dime package in. You can play with him at any point."

Now that he'll be playing closer to the ball and seeing more snaps in the tackle box or as an overhang defender, the 5-foot-9 Hartzog has bulked up. He's currently playing at 184 pounds — he was at 180 last season — with the goal of staying in the 185- to 187-pound range for the fall.

"This year I'm going to be more in the run fit, and in the RPO (run-pass option) window and stuff like that," Hartzog said. "I feel like that's going to be big for me, make a couple tackles and put that on tape, and still be a cover person. It's like the corner spot too, same technique, same things like that. So I feel like I'm in a good spot."

Hartzog said Nebraska's DBs have been watching film of the Buffalo Bills' past defenses since Butler was elevated to DC. While the DBs coach at Buffalo, Butler helped the 5-11, 192-pound Taron Johnson develop into one of the top nickels/slot corners in the NFL.

"This year there's more of a nickel focus, being down in the box and things like that," Hartzog said of Butler's defense. "Last year, sometimes I wasn't in the box, so his defense is putting people in different positions than they were at last year, and I like it."

A big part of spring ball is about moving different players around on the defense and seeing what sticks. Hartzog said DeShon Singleton, who last year played as the boundary safety, has been taking practice reps at the rover position and looks good doing it.

>> GAIN ALL-ACCESS with an annual or monthly subscription for less than $10/month

>> NEW SUBSCRIBERS get 30 days FREE

>> Sound off on the hot topics on our INSIDER'S BOARD

>> Follow us on Twitter (@NebraskaRivals)

>> Follow us on Instagram (@nebraskarivals)

>> Subscribe for FREE to the Inside Nebraska YouTube channel