Gregory, Valentine anchor defensive line

This week, ESPN.com has counted down the Nebraska position groups with most room to improve. And at the top of the list, it's a group not here for its lack of talent; rather, the opposite. With high ceilings, though, come high expectations.

Read up on the defensive line:

Major losses: Defensive end Jason Anrkah started 31 games over his final three seasons and achieved much-sought consistency last season to help lead a young front four. Tackle Thad Randle has been a fixture up front since 2010, fighting through chronic knee injuries to play his best football as a senior. Also gone in 2014 -- and perhaps for good -- is Avery Moss, who showed great potential last fall to earn a spot on ESPN.com’s Big Ten all-freshman team. Moss was banned from campus in January for one year, a ruling related to his conviction on a public-indecency count following a 2012 incident.

Top returnees: Randy Gregory was Nebraska’s best defender as a sophomore. The defensive end finished his first year at Nebraska with 10 ½ sacks, 18 quarterback hurries, 19 tackles for loss and 66 stops overall to earn first-team all-conference honors. At 6-foot-6, he dropped weight throughout the season, but his effectiveness never waned. Tackle Vincent Valentine stood out as a true freshman among a young group of returning interior players that includes Aaron Curry, Maliek Collins and Kevin Maurice.

Key question: Who fills the large hole left by Moss at the end position opposite Gregory?

Numbers to know: Since 2010, when Ndamukong Suh was chosen second overall in the NFL draft, just one Nebraska defensive linemen has been picked. The Huskers’ young linemen progressed a great deal last season, but they’ve seemingly only scratched the surface. After Oct. 1, Nebraska ranked 13th nationally and third in the Big Ten in allowing 3.36 yards per rush -- an impressive accomplishment after they surrendered 4.85 per rush through the first four games to rank 99th and 11th.

The outlook: Gregory is an All-America candidate. Valentine, at 6-foot-3 and 325 pounds, looks ready to grow into a great run stopper and anchor in the middle.

Others will fill the remaining spots, but whom? The Huskers hope to get some answers in the spring. In addition to Curry, Collins and Maurice, veterans Jay Guy, Tobi Okuyemi and Kevin Williams are back at tackle.

End Greg McMullen is largely untested but a candidate to fill Moss’ spot, as are redshirt freshman A.J. Natter and junior-college transfer Joe Keels, already on campus.

The Huskers will assess true freshmen Sedrick King, DeAndre Wills and Peyton Newell in August.

Countdown of Nebraska position groups with most room to improve:

No. 5: Secondary

No. 4: Quarterbacks

No. 3: Linebackers

No. 2: Tight ends

Check back next week for our countdown of Nebraska players to watch in spring practice.