Inexperience at Defensive End
The biggest question mark for the 2015 defense is how to replace both starters at defensive end in Deion Barnes and C.J. Olaniyan as well as key reserve Brad Bars. Barnes and Olaniyan may be equally difficult to replace- while Barnes excelled at creating havoc in the backfield, Olaniyan was a steady presence who was tremendous against the run and had a knack for showing up in big games.
Garrett Sickels and Carl Nassib seem to be set as the new starters, with Evan Schwan, Curtis Cothran and possibly redshirt freshman Torrence Brown waiting in the wings. Cothran and Schwan performed very well in the Blue-White Game, but we all know well enough that doesn't necessarily translate to anything meaningful in the fall. Brown could develop into a major force because of his freakish athleticism, but may also need a year to adjust to the collegiate game.
The potential is certainly there for the defensive end position not to miss a beat- heck, they could even improve upon the 2014 unit- but a few inexperienced players will need to take a major step forward. If not, Penn State's defense will not be so dominating without consistent pressure from a four-man front.
The Big Two and Who Else?
Penn State has two blossoming superstars in Brandon Bell and Nyeem Wartman-White who will take away the sting of replacing the ultra-productive Mike Hull. But does Penn State have the quality depth to replace them should one or both need to miss playing time this fall?
At the very least, the Nittany Lions have bodies at the position- quality, scholarship players waiting to take on a larger role. Jason Cabinda received valuable time on the field as a true freshman and could find himself as the starter opposite of Bell in 2015. Ben Kline returns after missing the 2014 season with a torn ACL and should be a key contributor. Gary Wooten, Von Walker and redshirt freshman Troy Reeder should all be able to contribute, but for the defense to remain dominant they just may have to depend on Bell and Wartman-White to survive the season.
Defensive coordinator Bob Shoop received some attention from a few major suitors after leading an improbable renaissance for the Penn State defense in 2014. Shoop even interviewed for the same position at LSU before deciding to return to Happy Valley, to the rejoice of Penn State fans everywhere. However, if Penn State once again produces one of the top defenses in the nation, there will be plenty more calling for Shoop with offers he may not be able to refuse. He won't just be getting offers for lateral positions either- he'll likely start collecting offers to become the next head coach at Big State U.
This may be a bitter pill for Penn State fans to swallow where unabated loyalty was always the norm, but it's something we will likely need to become accustomed to as long as the team finds success. If the Nittany Lions regain its status as one of the top programs in college football, there will be plenty others looking to poach the assistants, especially one with such a young coaching staff. The Ohio States and Alabamas of the world succeed with a revolving door of assistants, and hopefully Penn State will soon be in the position to do the same.
Bonus Reason: Too Much Time on the Field
I didn't want to include this as one of the three reasons since it is not a concern about the defense, but certainly a concern for the defense. The defense put up incredible numbers last season, especially considering all the time they spent on the field and all the awful field position they had to deal with. Think about all the times the defense did its job, then had to rush back on the field after a three-and-out or a quick turnover. The fact that the defense didn't completely fall apart by season's end is a minor miracle in itself. The offense must find a way to sustain drives n 2015 for the defense to truly live up to its potential.