There’s a saying in football that goes “everything starts up front,” meaning that the offensive and defensive lines are the most important components of their respective sides of the ball. That rings true for Penn State’s defense, because despite losing linebackers Mike Hull and Nyeem Wartman-White, Bob Shoop’s unit continues to be one of the best in the nation. While Jason Cabinda and Troy Reeder do deserve a ton of credit for their play, it’s clear that their lives are made easier by Penn State’s dominant defensive line. When Penn State is stuffing the run and also bringing adequate pressure with its front four, everybody has more freedom. Linebackers and safeties don’t have to cheat, and cornerbacks don’t have to stay in coverage long. Coaches can become more creative with their defensive play calling, whether it’s dropping back into zones or calling more blitzes.

Nittany Lion fans are familiar with the returning defensive tackle duo of Austin Johnson and Anthony Zettel. Both big men played big roles last season, and their elite level of play has continued into 2015. Johnson’s role has grown — he is now not only clogging up running lanes as a space-eater, but also breaking through the line of scrimmage to take down running backs and quarterbacks. Through the young season, Johnson has already tied his mark from last season with six tackles for loss, and has increased his sack totals from one last season to two and a half this season.

Zettel’s play has stayed steady too. While many will look at his low numbers of sacks (only half a sack through four games), that only tells half the story. He’s facing much more attention from the offensive line, opening up more opportunities for the guys next to him and behind him. Even with the extra attention, he’s still creating plenty of havoc in the backfield, on pace for another 15+ tackles for loss season.

Still, the defensive tackle play was to be expected. The concern heading into the season was at the defensive end where the Nittany Lions needed to replace Deion Barnes and C.J. Olaniyan. Stepping into the starting spots were Garrett Sickels and former walk-on Carl Nassib, two players who had shown promise, but were just merely rotation players in 2014. To say that they — especially Nassib — have lived up to expectations would be an understatement.

Nassib’s transformation from last year to this year is astounding. He’s gone from a nice player providing depth to leading the nation in sacks. That doesn’t happen often, and it’s a big reason why Penn State’s defense has taken its play to the next level. An edge rusher that can consistently get to the quarterback really changes the dynamic of the defense. That edge rusher is something that Penn State has lacked in years past — sure, guys like Barnes or Jack Crawford were solid players, but they weren’t able to get to the quarterback like Nassib’s been able to. Pairing up someone like Nassib next to two All-Big Ten-caliber defensive tackles makes it pretty obvious why the rest of the defense seems to click.

That’s not to forget Sickels, who has been good in his own right. As a redshirt sophomore, he’s the youngest of the group, but has been impressive this season and has made strides as a run defender. He’s been much more disciplined and consistent in 2015, which is all you can ask of him at this point. On that same token, the backups deserve some recognition too. Guys like Curtis Cothran, Parker Cothren, and Tarow Barney are providing valuable depth. When the second string comes in and the level of play doesn’t drop significantly, it keeps the starters fresh. That’s something that will pay dividends down the line.

While the schedule will get tougher for the Nittany Lions as they head into Big Ten play, look for Penn State’s defensive line to stay the same — dominant.