Spring practice is under way in the Big Ten, so let's take a look at what's on tap for the six teams in the Leaders Division.

ILLINOIS

Spring start: March 5

Spring game: April 12

What to watch:

1. Coaching staff makeover: Illinois players are used to coaching changes, and Tim Beckman's staff received a significant overhaul during the winter as five assistants departed the program (four voluntarily). The biggest change comes at offensive coordinator, as former Western Michigan head coach Bill Cubit takes over. Cubit has to implement his system and identify more playmakers with a unit that finished last in the Big Ten in both scoring and total offense last season.

2. Lines in limbo: The Illini not only lost significant pieces on both the offensive and defensive lines, but they have new position coaches at both spots as well. Defensive line has been Illinois' strongest spot, but the team must replace two future NFLers in Michael Buchanan and Akeem Spence. Glenn Foster is also gone, so the front four will have a very different look. The offensive line struggled mightily in 2012 and needs young players such as Michael Heitz and Ted Karras to take steps this spring.

3. Getting healthy: Illinois lost so many starters to injury in 2012 that it became difficult to get an accurate gauge on what Beckman could do with a healthy roster. Although linebacker Jonathan Brown and receiver Darius Millines will be limited this spring, the rest of the team is ready to go and Illinois added several potential big contributors from the junior college ranks. If Illinois has any chance of taking a major step in 2013, its best players must stay on the field this spring and allow the coaches a chance to evaluate and scheme for the season.

INDIANA

Spring start: March 2

Spring game: April 13

What to watch:

1. Quarterback cluster: While some Big Ten teams (Penn State, Purdue) have hardly any experience at quarterback, Indiana has three signal-callers who have logged significant field time. Tre Roberson, who started the 2012 season before suffering a broken leg in Week 2, returns this spring, and it will be interesting to see how he looks and whether he outperforms Cameron Coffman and Nate Sudfeld. Coffman started the final 10 games last fall and passed for 2,734 yards and 15 touchdowns, while Sudfield added 632 passing yards and seven TDs. Indiana's quarterback depth is a good problem to have, but it would be good to see some separation this spring.

2. Defensive leadership: Fielding a Big Ten-level defense remains Indiana's top priority, and the Hoosiers need leaders to develop this spring. Top linemen Adam Replogle and Larry Black Jr. depart, and Indiana needs to build depth up front after allowing a league-worst 231.3 rush yards per game in 2012. Linebacker is another spot IU must upgrade, and David Cooper should be ready to take the reins after recording 86 tackles in 12 starts a year ago. Like Illinois, Indiana also welcomes several junior college defenders, including tackle Jordan Heiderman.

3. Secondary surge: All the question marks in Indiana's defensive front seven make it even more important for the secondary to make strides this spring. The Hoosiers have no shortage of experience in the back four with players such as Greg Heban, Mark Murphy, Brian Williams (12 starts last season) and Antonio Marshall (started final seven games). There's potential for the secondary to be a strength for IU in 2013, but the group must make more plays after recording a league-low seven interceptions last fall.

OHIO STATE

Spring start: March 5

Spring game: April 13 (at Paul Brown Stadium, Cincinnati)

What to watch:

1. Taking a pass: The highest-scoring offense in the Big Ten returns every starter but two, and all that experience, talent and familiarity with the spread attack heading into Urban Meyer's second season with the Buckeyes figures to make them even more dangerous. The key will be how much more efficient Braxton Miller can become as a passer.

2. Getting defensive: For all the pieces the offense retains, the defense is a completely different story heading into spring camp. The Buckeyes have to replace the entire defensive line after losing three seniors and junior Johnathan Hankins to the draft, two starting linebackers are gone and the graduation of cornerback Travis Howard leaves an additional hole in the safety. There will be no shortage of competition for first-team reps.

3. Looking for leaders: Meyer and the senior class that has since departed quickly forged a deep bond, and he has gone out of his way to praise those players' leadership as integral in the unbeaten season that started his tenure with the Buckeyes. Now he needs a new wave of emotional speakers and relentless workers to take the torch from the likes of John Simon and Zach Boren, and Meyer will be making a point to identify his best candidates over the 15 workouts leading into the summer.

-- Austin Ward, BuckeyeNation

PENN STATE

Spring start: March 18

Spring game: April 20

What to watch:

1. Quarterback competition: With the departure of fifth-year senior Matt McGloin, quarterback is now the biggest question mark on this team. Sophomore Steven Bench has a head start and will compete against juco early enrollee Tyler Ferguson. Christian Hackenberg won't join the team until summer. Can this no-huddle offense be as effective?

2. Replacing LBs Michael Mauti and Gerald Hodges: Mike Hull, who usually played inside, will have to make some adjustments as one of the expected replacements for the All-Big Ten linebacker tandem. The other spot is up for grabs, and fans should expect to see a battle between Ben Kline and Nyeem Wartman.

3. New faces at WR, TE: Redshirt freshman Eugene Lewis, the headliner of PSU's 2012 class, could challenge Brandon Moseby-Felder as the No. 2 WR target. Adam Breneman, the No. 1 tight end recruit in the country, is also hoping to be recovered from a torn anterior cruciate ligament in time for the Blue-White Game. Both could be stars down the road for PSU.

-- Josh Moyer, NittanyNation

PURDUE

Spring start: March 18

Spring game: April 13

What to watch:

1. Behind these Hazell eyes: Yes, I'll justifiably take the abuse for the Kelly Clarkson reference, but new Purdue coach Darrell Hazell has his first chance to evaluate his team on the field this spring. Hazell brings a completely new coaching staff and a new approach to Purdue, which fell short of expectations in 2012 and has significant questions on both sides of the ball. He seems to be getting good buy-in from the players so far, but it'll be interesting to see how things progress during the 15 workouts this spring.

2. Quarterback race: If you like mysteries, you'll enjoy Purdue's quarterback competition this spring. The combination of a new coaching staff and unproven but talented candidates makes the race virtually impossible to predict. Hazell and new offensive coordinator John Shoop will study redshirt freshman Austin Appleby, who could have a slight edge to win the job, along with redshirt freshman Bilal Marshall and early enrollee Danny Etling, a decorated recruit. Don't forget about Rob Henry, who started in 2010 and would have been the top quarterback in 2011 if not for an ACL injury weeks before the season.

3. Short stopper: Purdue has to find a replacement for standout defensive tackle Kawann Short, the centerpiece of the defensive line the past few seasons. Bruce Gaston Jr. will continue to occupy the other top tackle spot, but there will be plenty of competition to join him in the starting lineup. Purdue's defensive line underachieved in 2012, and while Gaston and ends Ryan Russell and Ryan Isaac all return, the Boilers will really miss Short's production if they don't build more depth up the middle.

WISCONSIN

Spring start: March 9

Spring game: April 20

What to watch:

1. New era dawns: Consistency is the norm at Wisconsin, but players will have to adjust to a dramatically different coaching staff for the second consecutive season. This time, it includes a new leading man in Gary Andersen, who gets his first chance to work with the players on the practice field. Andersen doesn't plan to overhaul the schemes, but he and his coaches will put their spin on things and see what works. He'll also bring a different personality to practice but one that athletic director Barry Alvarez thinks will fit the program's culture.

2. Intrigue at quarterback: Arguably no team in America has a more interesting quarterback race than the Badgers do this spring. They have three players with starting experience -- Joel Stave, Curt Phillips and Danny O'Brien -- plus a talented redshirt freshman (Bart Houston) who arrived as a decorated recruit and a junior college addition (Tanner McEvoy) brought in by the new coaches. Add in a new system under coordinator Andy Ludwig, and it's anyone's guess who will separate himself this spring. Be sure to tune in.

3. Secondary in the spotlight: The Badgers lose three of four starters in the secondary from the 2012 squad, including top cornerbacks Devin Smith and Marcus Cromartie. The new staff is aware of the numbers issue and signed junior college All-American Donnell Vercher earlier this month. Other players who will compete for starting spots include cornerbacks Darius Hillary and Peniel Jean and safeties Michael Trotter and Michael Caputo. Wisconsin hopes to have some answers in the back four by the end of the spring.