BATON ROUGE, La. – Shutting down the run is a matter of pride for the Tigers, and Dave Aranda did not disappoint in his debut season as LSU’s defensive coordinator.

In 2016, LSU ranked 13th in the nation in rushing defense (117.3 yards per game) while surrendering just seven touchdowns on the ground, good for second in the SEC.

After successfully transitioning the Tigers into his 3-4 system,  Aranda faces another challenge this season: replacing the Tigers’ annual exodus of NFL talent.

Along the defensive line, LSU looks to replace DE Lewis Neal, DT Davon Godchaux and DE Tashawn Bower, a group that tallied 145 tackles last season. Senior DE Christian LaCouture returns after recovering from an ACL tear before the start of last season.

The Tigers will miss first-round draft pick Jamal Adams’ physicality in the box, leaving the secondary’s key position for intimidation open for competition.

As a stellar crop of 3-4 recruits settles in, the success of the Tigers’ run defense might hinge on the how well four highly recruited freshman linebackers – K’Lavon Chaisson, Jacob Phillips, Patrick Queen and Tyler Taylor – adjust to Aranda’s system.

Rushing yards allowed per game (SEC rank): 117.3 (2nd)

Most yards allowed in 2016: 216 yards, Alabama

Rushing TDs allowed: 7 (2nd)

100-yard rushers allowed: Alabama’s Jalen Hurts (20 carries, 114 yards, 1 TD); Florida’s Jordan Scarlett (22 carries, 108 yards); Arkansas’ Keith Ford (15 carries, 100 yards).

Front seven

Despite the loss of Godchaux, Bower and Neal, who combined for 19.5 tackles for loss last season, LaCouture’s return gives the Tigers a proven run stopper to anchor their front.

LaCouture thrived as a defensive tackle in the Tigers’ 4-3 front during his first three seasons at LSU, tallying 86 tackles and 8 tackles for loss. Although moving outside to defensive end in Aranda’s 3-4 scheme, LaCouture brings experience and an in-depth understanding of  Aranda’s schemes after a year spent as an unofficial assistant D-line coach.

Senior Greg Gilmore returns inside after notching 34 tackles as the Tigers’ starting nose tackle last season.

Aranda bolstered the Tigers’ interior depth with freshman Tyler Shelvin, the consensus top player in Louisiana for the Class of 2017 . Shelvin, at 6-2 and 380 pounds, fits the mold of a powerful, run-stuffing nose tackle crucial to the 3-4 defense.

While LaCouture leads the defensive line, Devin White will spearhead the Tigers’ linebackers against the run in the void left by former Tiger standouts Kendell Beckwith and Duke Riley.

White flashed his potential to create havoc in the backfield during his two starts last season. White’s background as a running back coupled with his athleticism allows him to lay fierce hits on backs in the backfield and the open field alike, like this hit and strip of Trayveon Williams against Texas A&M in 2016.

Along with White, the Tigers will rely on veteran Donnie Alexander to help the program’s stellar haul of freshman linebackers adapt quickly.

Who is the secondary enforcer?

For the first time in two seasons, the Tigers lack a punisher in the secondary, allowing a host of contenders to clash for the title.

After breaking into the starting lineup last season at free safety due to an injury, junior safety John Battle spent the spring in the weight room preparing to play more in the box. The Hallandale, Fla., product looks to return partly to the physical style of play he made his name on during his prep career as he continues to build on his reputation as a high IQ player in Baton Rouge.

Senior safety Ed Paris Jr. aims to emerge as a starter after spending his first three campaigns overshadowed by the likes of Adams and former Tigers’ star Jalen Mills. Despite appearing in 37 games as a Tiger, Paris has recorded only two starts, fueling his drive to make a mark with hard hits this season.

Besides the Tigers’ two expected veteran starters, freshman Grant Delpit is a dark horse to become an enforcer against the run. In the Tigers’ shortened spring game, Delpit shined with hard hits, reminiscent of the playmaking ability Adams displayed early in his career.

With the inexperience in the second level of the defense, the Tigers secondary will need to step up in run support early in the season by filling in gaps as LSU breaks in new starting linebackers.

Greatest concern

Although the Tigers are accustomed to reloading their talent on defense, replacing experience will be a harder task this season.

Like every 3-4 scheme, Aranda’s defense relies on the linebackers, one of the Tigers’ least experienced units, featuring 11 underclassmen.

White and Alexander, LSU’s veteran ‘backers, have notched just five starts.

But then again, lack of experience was a knock against the Tigers’ 2016 defense, and Aranda worked his magic. This season could be the start of Aranda showcasing his ability to develop young defenders into elite playmakers early in their careers.

One stat that needs to change

Despite the Tigers’ overall dominant run defense, LSU’s season comes down to its performance against Alabama, which has been the exception to the Tigers’ norm of stout defense in the last five seasons.

In LSU’s five consecutive regular-season losses to the Crimson Tide since its 9-6 win in 2011, the Tigers have allowed 186.2 rushing yards per game comparative with 139.9 in conference games during those seasons.

The concerning trend for Aranda and company has been the Tigers’ defensive meltdowns when the rivals clash in Tuscaloosa. In the two games in Bryant-Denny Stadium since 2012, Alabama has tallied 443 combined yards on the ground, averaging 4.6 per carry.

Aranda made a statement in his first bout with the Crimson Tide last season, holding Alabama scoreless through three quarters.

For the Tigers to contend with Alabama for the SEC West crown, LSU must be able to figure out how to keep the Crimson Tide from imposing its will on the ground, particularly in Bryant-Denny.

Better or worse in 2017

In 2016, Aranda molded a defense of 4-3 talent into a dominant 3-4 scheme against the run.

Despite the addition of his first class of stellar 3-4 recruits, the loss of experience at every level of the defense, particularly at linebacker, will catch up with LSU in its rush defense.