Arkansas’ brutish offensive line and sexy production in the running game got the most credit for last year’s turnaround.

But coach Bret Bielema couldn’t have engineered a winning season and a Texas Bowl victory without a smothering defense that at times looked like the best unit in the SEC.

Because coordinator Robb Smith arguably lost the four best players from that group, there are concerns about whether the defense can remain impenetrable, especially as the Razorbacks enter the fall with elevated expectations.

ESPN recently posted an article debating whether or not Bielema will win 10 games in his third season coaching the Hogs — mind you, the team won just three games in ’13. “Though the Hogs lost some valuable guys from their front seven, this defense should still be strong, especially with a deeper — and maybe more athletic — defensive line,” ESPN wrote.

And there’s the crux of the matter.

Arkansas will try to make its offense more efficient, tinkering with a few of the offensive line positions and employing former Central Michigan coach Dan Enos to try to build some semblance of a downfield passing game, but the team’s offense — both in personnel and scheme — should be more or less a carbon copy of last year’s.

If the Razorbacks are to maintain last year’s record, much less pick up an additional three SEC wins, Arkansas must a) improve its record in one-possession games, and b) find a way to maintain the level of play within the defensive front seven.

But, as ESPN alluded to, the team should do just that.

Trey Flowers, one of the SEC’s best run-stuffing defensive ends in years, spearheaded the Bermuda Triangle, which spearheaded one of the nation’s toughest run defenses in 2014. This year’s iteration doesn’t have a talent as prodigious as Flowers, who gave SEC offensive linemen all sorts of difficulties.

Darius Philon was an above-average SEC interior rusher who knew how to make himself small and slip between cracks that should be impassable for a 271-pound man.

The team’s accomplishments last fall bear repeating. This front seven wasn’t merely good. Effusive praise may fail to capture how dominating the group became at times last season. Arkansas’ front seven bludgeoned the likes of Alabama, LSU and Texas into a combined 104 rushing yards(!).

The Razorbacks defense got into a remarkable groove after September, holding down several ranked opponents. No. 7 Alabama (14 points), No. 1 Mississippi State (17 points), No. 20 LSU (0 points), No. 8 Ole Miss (0 points) and No. 17 Missouri (21 points) each languished against Arkansas in October or November.

Back to the Bermuda Triangle: all three players got selected in the NFL draft, along with cornerback Tevin Mitchel. That’s a lot of top-end talent to replace for a coaching staff that has signed just four defensive players rated as four-star high school talents since arriving in Fayetteville, Ark., in 2013. Not to mention, not a single Arkansas defender made Phil Steele’s preseason All-SEC teams — which include a second, third and fourth unit.

Conveniently, all four of those touted signees are defensive linemen: Bijhon Jackson, Hjalte Froholdt, Jeremiah Ledbetter and Jamario Bell. At this point all of those players represent depth. They’ll all play a role, but that’s also an indication of how strong the team’s starting defensive line will be.

Taiwan Johnson should be a fine approximation of Philon as an interior pass rusher. JaMichael Winston, Tevin Beanum, Deatrich Wise Jr. and Ledbetter can’t match Flowers, but collectively, Arkansas’ defensive ends could be even better this fall. Certainly such a deep rotation will keep those players fresh well into the second half of SEC games in November, when big offensive lines often try to demoralize opponents in the running game.

The linebackers are thin and the secondary allowed 12 passes of at least 40 yards last season, to the Razorbacks are susceptible to an occasional blown coverage or missed tackle on the back end.

But teams like LSU and Ole Miss, depite talented receivers, remain without a viable, sure-thing starting quarterback to take advantage, while Mississippi State’s offensive line may not be able to hold up under a barrage of attacks from Arkansas.

There are questions about the Razorbacks defense in ’15, but they’re probably overblown. Expect the unit to remain one of the best in the SEC, and drive the team’s efforts to improve its win total as much or more than the offense this fall.