Editor’s note: This is part of a daily series counting down to Penn State’s Blue-White Game April 18.

Entering the 2015 season, Penn State’s defensive front four is poised for another dominating year. The loss of Deion Barnes will hurt, but with the return of Anthony Zettel and Austin Johnson in the middle and the emergence of Carl Nassib, the Nittany Lions will have their fair share of talent along the defensive line.

For a team that finished last season ranked first nationally in rush defense (84.8 yards per game) along with 87 tackles for loss and 30 sacks, both top-30 marks nationally, the goal for 2015 will be to maintain that high level of production. For Penn State’s defense, that starts with the big guys up front.

Let’s take a closer look at Penn State’s defensive line heading into the Blue-White Game.

Who’s Leaving

DE Deion Barnes, DE C.J. Olanyian

Any way you slice it, the fact of the matter is Penn State needs to replace a pass-rushing duo that combined for nine sacks last season, 30 percent of its end-of-season total. Barnes and Olanyian will both try to take their talents to the NFL, and while nobody is more excited about sending players to the pros than James Franklin, he’d rather have Barnes back for another season terrorizing opposing quarterbacks. Losing pass rushing talent is the last thing defensive line coach Sean Spence wants to see, but with Penn State finally back to a full compliment of scholarships, depth in the rotation will be a key factor moving forward.

Who’s Returning

DT Anthony Zettel, DT Austin Johnson, DE Carl Nassib, DT Tarow Barney, DT Parker Cothran, DE Garrett Sickels, DE Torrence Brown, DE Evan Schwan

Anthony Zettel broke out in a big way last season, leading the Nittany Lions in sacks (8.0) and tackles for loss (17.5) en route to being named first team All-Big Ten. Zettel’s partner up front, 6-foot-4, 325 pound Austin Johnson, was a monster against the run, amassing 49 total tackles, the fourth-most on the team, including six tackles for loss, one sack, and two fumble recoveries. The Lions have two of the best defensive lineman in the conference, which will only help younger players develop by competing against the best every single practice.

“Having a 327 pound dancing bear like A.J. Johnson inside that you’re dealing with, then the quickness and explosion of Zettel, that’s going to challenge those guys,” Franklin said of his men in the middle.

On the edge is where things are a bit more unclear. With Barnes and Olanyian gone, a number of key reserves and rotation players will be called upon to take the starting job. After offseason workouts, James Franklin made it clear who was in the running to be Penn State’s next dominant pass rusher.

“Nassib I think had a sneaky, quiet, really successful year, if you go back and really study his tape,” Franklin said of the senior from West Chester, Pa., who racked up 3.5 tackles for loss and one sack last season. “He played really well for us, going back and watching the tape on him.”

“He’s Mr. Consistent,” Franklin added. “He does everything right. He’s extremely strong, extremely athletic. Comes from an unbelievably athletic family. He has the work ethic, the mentality, intelligence. I think he’s a premed major doing extremely well.”

Biggest Strength – Depth

It’s shocking to say the least, but for the first time in four seasons, depth will be one of Penn State’s strengths, especially on the defensive line. At his press conference previewing spring practice, Franklin said the team has a legitimate two deep at every position, a luxury the Nittany Lions haven’t had in quite some time.

Not only is Franklin happy with the depth, but the quality of players taking the field on the front four.

“What’s exciting about our defensive ends, as big as they are, they still look skinny, and they’re moving better,” Franklin said. “So all of their agility, all their 40 times went down, and they all put on between 12 and 15 pounds. Right now we have five guys over 250 pounds that power cleaned 335 pounds or more.”

Among the candidates to earn the two vacant starting spots on the edge, Franklin rattled off basically the entire roster: Sickels, Schwan, Nassib, Cothran, and Brown, as well as second-year freshman Will Eikenberry and true freshman Colin Castagna. It’s a good problem to have as spring practice gears up, with Franklin hoping to whittle down his choices after Blue-White weekend.

Biggest Weakness – Experience

Zettel and Johnson are the two most-experienced starters left on the defensive line, and are the Lions’ two best lineman to boot. However, Franklin admitted before spring practice that experience was the one issue plaguing the front four.

But given the departure of two senior leaders up front, Franklin is happy where the defensive line stands. He’s modeling his approach after another conference opponent (he won’t say which one), and given the players on the roster, the experience at defensive end is right where he wants it to be.

“You look at programs, to me our [defensive ends] are exactly what you want our program to be like in a year or two,” Franklin said. “Yes, they are new starters, but they’ve played now and they’ve sat behind players or played a limited role behind players for two years. That’s what you want.”

The second-year coach mentioned Sickles, Schwan, and Nassib, players that had limited roles in reserves but had success when they were on the field. In addition to rotating in and out up front, Parker Cothran cut his teeth on special teams.

“There’s a big difference between that being your inexperience compared to your inexperience being redshirt freshmen and true freshmen playing for you, if that makes sense,” Franklin added.

“I think our defensive ends are a great example of that.”

Overall

Despite having some question marks at the defensive end position, the defensive line heads into the thick of spring ball as one of Penn State’s strongest units. Zettel and Johnson are poised to deliver stellar seasons as the bedrock of the team’s stifling rush defense, book-ended by a combination of athletic, lengthy defensive ends with speed. After a brilliant 2014 season, Zettel has the potential to become a world-class player, already being named one of Sports Illustrated’s 12 Big Ten players to watch.

While it will be up to Franklin and coach Spence to figure out the final rotation, the front four is expected to be the strength of Penn State’s defense. The unit will be called upon to do even more, especially given the loss of Mike Hull at linebacker, but Zettel, Johnson & Co. should be up to the task. Should one of Carl Nassib, Evan Schwan, or Garrett Sickels have a breakout season as an edge rusher, you could be looking at one of the nation’s best defensive lines.