Spring preview: Defensive line

As the start of spring practice on Mar. 2 draws closer, continues our in-depth look at each position with our 2013 spring position previews.
Today, we analyze and breakdown the defensive line heading into spring practice.
What we know right now: Depth was a major issue on the defensive line last season and could be again this year. With Baker Steinkuhler as the only truly reliable defensive tackle, the coaches moved end Cameron Meredith inside, hurting his pass-rushing opportunities and leaving Eric Martin as the lone above-average rusher. All three players are gone now.
Their replacements all have potential but next to no experience. At end, JUCO transfer Randy Gregory has the talent to be a beast but has yet to play a down of Division I football and missed all last season with a broken leg. Joining him are redshirt freshmen Greg McMullen and Avery Moss, both of whom could be productive players but are relative unknowns due to lack of playing time (Moss played sparingly in three games before receiving a medical redshirt). Someone from the freshmen group of Dimarya Mixon, Ernest Suttles and A.J. Natter will likely be expected to contribute because none of the other veterans on the roster have proven worthy of playing time.
Experience is also a scarcity at tackle. In addition to the departures of Steinkuhler and Meredith, Chase Rome left the team after the season. That leaves Thad Randle as the position's only experienced player, and his injury history makes him a far from reliable option. Kevin Williams and Aaron Curry both return after seeing surprisingly little playing time last year and will both be asked to contribute. Vincent Valentine redshirted last season but is expected to play a major role in the coming seasons. He has the potential to have a big impact. Freshmen Kevin Maurice and Maliek Collins could provide depth if they don't redshirt.
Biggest question to answer: What can Jason Ankrah give Nebraska in his senior season? The senior came to NU as a highly-regarded recruit but has not produced much. In three seasons, he has just three sacks, including two last year, and 45 total tackles. That's simply not enough production from a player who has started 18 games over the past two seasons.
Ankrah is more important than ever this year because he is by far NU's most experienced defensive linemen. Much will be asked of him as the new guys and youngsters find their way on the field and figure out their roles in Bo Pelini's defense. The coaching staff said Ankrah could very well move inside to help provide depth at tackle. Wherever he lines up, his production needs to increase this year.
Spring dark horse: McMullen. It's tough to project his impact without seeing him on the field, but he certainly looks the part at 6-foot-3 and 280 pounds and was a four-star recruit in the 2012 class. He piled up more than 40 sacks in his high school career, including 12.5 in his senior season. For a team that struggled to get to the quarterback even with Martin on the roster, McMullen could be part of the solution to NU's pass-rushing problems.