As Scott Satterfield has hit the ground running as Louisville's new head football coach, we close the year with a three-part series examining how Satterfield's team will look. We continue today with the defense.

In his introduction to the media last week, Louisville defensive coordinator Bryan Brown said his defense would fly to the football. That’s a philosophy that most coaches embrace — Brian VanGorder, for instance, preached it before and during a miserable season in which his defense ranked 128th in points allowed.

But Brown had film to back up his point. He mentioned a play from this past season, when Brown was Scott Satterfield’s defensive coordinator at Appalachian State. On a safety against Coastal Carolina, his defense really did have nine men piled up in the end zone to take down the ball carrier.

Part 1:Scott Satterfield's best offenses have been built around reinvention

Appalachian State had the opposing offense pinned at its own 1-yard line in the fourth quarter. Coastal Carolina ran a dive up the middle. Safety Desmond Franklin flew up the middle and leveled the running back, but he didn’t go down. Inside linebacker Jordan Fehr stuffed the back again, and before long, just as Brown said, there were eight white jerseys keeping the ball in the end zone.

“We play a couple defenses, and a couple wrinkles here and there,” Brown said. “But the guys just love to fly around and have fun, and one thing we’re going to do is chase that football.”

Louisville fans have to hope that credo is legitimate this time.

A shake-up on defense could be both a blessing and a curse. The 2018 season wore on Louisville’s defense especially, as its best player, Jonathan Greenard, suffered a season-ending knee injury in the first quarter of the first game and a handful of other starters went down during the season.

More:Jonathan Greenard, a key piece of Louisville's defense, will transfer

The Cardinals didn’t have any standout playmakers, so they let other teams roll down the field. They were the first Power 5 team ever to give up more than 50 points in five straight games. By the end, some admitted being demoralized.

Brown brings a much-needed energy boost.

But he is also the program’s fourth defensive coordinator in four years, and he and Satterfield run a defensive scheme very different from any of the first three. They will deploy a 3-4 front, as opposed to VanGorder’s 4-2-5 package, featuring fewer linemen and defensive backs but more linebackers.

“It’s an aggressive defense that creates turnovers and it does not give up big plays,” Satterfield said at his introductory press conference. “We are going to run and hit and stay on top. Match the numbers and chase the football. It’s very simple and I think (it) will be a great product defensively to have here.”

“Match the numbers” is key for a Louisville program that has to face, for example, both Syracuse’s no-huddle spread offense and Boston College’s tight end-heavy, power formation every year. Too often, the Cards came out with five defensive backs in the game who struggled to tackle Boston College running back AJ Dillon.

Plays like the safety against Coastal Carolina are useful, then. Appalachian State lined up in its normal 3-4 formation, but with eight men in the box — three down linemen, four linebackers and an extra safety — to counter the stacked offensive front. The Mountaineers play some snaps with as few as five players in the box to put men in coverage against a five-wide set.

That’s what has been missing at Louisville, and one important need for improvement is putting players in the right spots. Some defensive ends in the four-man front become outside pass rushers in the 3-4. Nickel backs will play only in certain situations, not every down.

And there’s room for two middle linebackers, which is good for Louisville, because the roster features two talented ones, Dorian Etheridge and Robert Hicks, with at least two years of eligibility left.

Brown was optimistic, saying he thinks many of the players he inherited will fit well into certain positions in his defense.

The top priority has to be teaching the new scheme to a group of defenders that often looked out of place this season. Brown was optimistic about that, too.

“Our defense is not tough,” Brown said. “It’s not hard to learn. It’s very, very simple. A lot of teams think your defense is really, really complicated. It’s really not. I hope they keep thinking that way, that it’s really, really complicated. That means we’re doing a good job.”

More coverage:Satterfield, Louisville football coaches know what a rebuild will take

The 35-year-old coordinator is an up-and-coming coach, one of the participants in the national football coaches association’s 35 Under 35 leadership institute.

Under Brown, Appalachian State improved from No. 44 to No. 5 in the country this season in yards allowed per play. The Mountaineers have fielded top-25 defenses in three of their five seasons in the Football Bowl Subdivision, which was one quality that intrigued athletic director Vince Tyra about Satterfield.

The 3-4 defense gives Louisville an opportunity to bring pressure off the edge, too, as opposed to primarily up the middle, as it did this past season with Etheridge and outside linebackers C.J. Avery and P.J. Blue. Appalachian State had a defender with more than 100 tackles in four of Satterfield’s six seasons. Louisville has not had one since Keith Kelsey in 2015.

The Mountaineers don’t jump off the page with their sack production, but they’re terrific at limiting explosive plays, ranking in the top 15 in three of the past four years — No. 1 in 2016 — in plays of 20 or more yards allowed.

Appalachian State was also a top-20 team in forcing turnovers the past two seasons. Perhaps that, more than anything, signifies the philosophy Brown was so eager to discuss.

“You may make mistakes, but you’re going to get to that football,” Brown said. “If you’re not getting to that football, you won’t play for us here.”

Jake Lourim: 502-582-4168; jlourim@courierjournal.com; Twitter: @jakelourim. Support strong local journalism by subscribing today: www.courier-journal.com/jakel.