We're taking snapshots of each position group with each Big Ten team entering the spring. Up next: the defensive lines.

Illinois: This is a significant concern for the Illini, especially after the recent departure of Houston Bates, who started last season at the Leo (defensive end/outside linebacker) spot. Illinois also loses its other starting defensive end, Tim Kynard. The team will rely heavily on junior-college players such as Jihad Ward and Joe Fotu, but it also needs holdovers like Dawuane Smoot and Paul James III to step up on the perimeter. Illinois returns more experience inside with Austin Teitsma and Teko Powell, but there should be plenty of competition, especially with the juco arrivals, after finishing 116th nationally against the run.

Indiana: The anticipated move to a 3-4 alignment under new coordinator Brian Knorr creates a different dynamic for the line this spring. Indiana must identify options at the all-important nose tackle spot, and possibilities include sophomores Ralphael Green and Darius Latham, both of whom are big bodies. Nick Mangieri had a nice sophomore season and should be in the mix for a starting job on the perimeter (end or outside linebacker), while David Kenney could be a good fit as a 3-4 end. Defensive end Ryan Phillis is the team's most experienced lineman, and Zack Shaw also has some starting experience.

Iowa: This group should be the strength of the defense as Iowa returns three full-time starters -- tackles Carl Davis and Louis Trinca-Pasat, and end Drew Ott -- as well as Mike Hardy, who started the second half of the season opposite Ott. End Dominic Alvis departs, but Iowa brings back almost everyone else from a line that allowed only eight rushing touchdowns in 2013. Junior Darian Cooper could have a bigger role and push for more playing time inside, and Nate Meier provides some depth on the perimeter after recording two sacks in 2013. Iowa is in good shape here.

Maryland: The Terrapins employ a 3-4 scheme and appear to be in good shape up front, as reserve Zeke Riser is the only rotation player to depart. Andre Monroe leads the way at defensive end after an excellent junior season in which he led Maryland in both sacks (9.5) and tackles for loss (17). Quinton Jefferson started at defensive end last season and recorded three sacks. There should be some good competition this spring at nose tackle between Keith Bowers and Darius Kilgo, both of whom had more than 30 tackles last season. The challenge is building greater depth with players such as end Roman Braglio.

Michigan: If the Wolverines intend to make a big step in 2014, they'll need more from the front four, which didn't impact games nearly enough last fall. Michigan's strength appears to be on the edges as veteran Frank Clark returns after starting every game in 2013 and recording a team-high 12 tackles for loss. Brennen Beyer, who started the second half of last season, is back at the other end spot, and Michigan has depth with Mario Ojemudia and Taco Charlton. There are more questions inside as Willie Henry, Chris Wormley and others compete for the starting job. Young tackles such as Henry Poggi and Maurice Hurst Jr. also are in the mix, and Ondre Pipkins should be a factor when he recovers from ACL surgery.

Michigan State: The Spartans return the best defensive end tandem in the league as Shilique Calhoun, a second-team All-American in 2013, returns alongside Marcus Rush, one of the Big Ten's most experienced defenders. Joel Heath, Brandon Clemons and others provide some depth on the perimeter. It's a different story inside as MSU loses both starters (Micajah Reynolds and Tyler Hoover), as well as reserve Mark Scarpinato. Damon Knox, James Kittredge and Lawrence Thomas, who has played on both sides of the ball, are among those who will compete for the starting tackle spots. If Malik McDowell signs with MSU, he could work his way into the rotation.

Minnesota: Defensive tackles like Ra'Shede Hageman don't come around every year, and he leaves a big void in the middle of Minnesota's line. The Gophers will look to several players to replace Hageman's production, including senior Cameron Botticelli, who started opposite Hageman last season. Other options at tackle include Scott Ekpe and Harold Legania, a big body at 308 pounds. Minnesota is in much better shape at end with Theiren Cockran, arguably the Big Ten's most underrated defensive lineman. Cockran and Michael Amaefula both started every game last season, and Alex Keith provides another solid option after recording five tackles for loss in 2013.

Nebraska: Other than MSU's Calhoun, Nebraska returns the most dynamic defensive lineman in the league in Randy Gregory, who earned first-team All-Big Ten honors in his first FBS season. If the Huskers can build around Gregory, they should be very stout up front this fall. Nebraska won't have Avery Moss, suspended for the 2014 season, and players such as Greg McMullen and junior-college transfer Joe Keels will compete to start opposite Gregory. The competition inside should be fascinating as junior Aaron Curry and sophomore Vincent Valentine both have starting experience, but Maliek Collins came on strong at the end of his first season and will push for a top job.

Northwestern: It will be tough to get a clear picture of this group in the spring because of several postseason surgeries, but Northwestern should be fine at defensive end despite the loss of Tyler Scott. Dean Lowry, Ifeadi Odenigbo and Deonte Gibson all have significant experience and the ability to pressure quarterbacks. Odenigbo, who had 5.5 sacks as a redshirt freshman, could become a star. The bigger questions are inside as Northwestern must build depth. Sean McEvilly is a solid option but must stay healthy. Chance Carter and Max Chapman are among those competing for starting jobs at tackle.

Ohio State: A total mystery last spring, the defensive line should be one of Ohio State's strengths in 2014. Noah Spence and Joey Bosa could become the Big Ten's top pass-rushing tandem, and the Buckeyes have depth there with Jamal Marcus, Adolphus Washington and others. Returning starter Michael Bennett is back at defensive tackle, and while Joel Hale might move to offense, there should be enough depth inside with Tommy Schutt, Chris Carter and Washington, who could slide inside. Nose tackle is the only question mark, but new line coach Larry Johnson inherits a lot of talent.

Penn State: Like the rest of the Lions defense, the line struggled at times last season and now much replace its top player in tackle DaQuan Jones. The new coaching staff has some potentially good pieces, namely defensive end Deion Barnes, who won 2012 Big Ten Freshman of the Year honors but slumped as a sophomore. Barnes and C.J. Olaniyan could form a dangerous pass-rushing tandem, but they'll need support on the inside, where there should be plenty of competition. Austin Johnson will be in the mix for a starting tackle spot, and early enrollees Tarow Barney and Antoine White also should push for time. Anthony Zettel provides some depth on the perimeter.

Purdue: The line endured a tough 2013 campaign and loses two full-time starters (tackle Bruce Gaston Jr. and end Greg Latta), and a part-time starter (end Ryan Isaac). Competition should be ramped up at all four spots this spring. Senior end Ryan Russell is the most experienced member of the group must take a step this offseason. Evan Panfil and Jalani Phillips will push for time at the end spots, along with Kentucky transfer Langston Newton. The group at tackle includes Ryan Watson and Michael Rouse III, both of whom started games in 2013.

Rutgers: Keep a close eye on this group in the spring as Rutgers begins the transition to the Big Ten. The Scarlet Knights lose two starters in end Marcus Thompson and tackle Isaac Holmes, as well as contributor Jamil Merrell at tackle. Darius Hamilton provides a building block on the inside after recording 4.5 sacks and 11.5 tackles for loss in 2013, and end Djwany Mera is back after starting throughout last season. David Milewski played tackle last year, but both he and Hamilton likely need to add weight for their new league. Rutgers has some talent in the younger classes and needs players such as Sebastian Joseph, Kemoko Turay and Julian Pinnix-Odrick to emerge.

Wisconsin: Linebacker Chris Borland is the biggest single departure for the Badgers' defense, but the no position group loses more than the line. Wisconsin must replace several mainstays, most notably nose tackle Beau Allen, who performed well in the first year of the 3-4 set under coordinator Dave Aranda. Senior Warren Herring will step in for Allen after three years as a reserve. Konrad Zagzebski is a good bet to fill one of the end spots, but there will be plenty of competition with players such as Jake Keefer, James Adeyanju, Arthur Goldberg and Chikwe Obasih.