While many already assumed that junior transfer Tanner Lee would enter the offseason as the frontrunner to win Nebraska's starting quarterback job, head coach Mike Riley made it clear earlier this week that the competition had only just begun.

Riley said that Lee and redshirt freshman Patrick O'Brien would go into the start of spring ball essentially as co-No. 1s, with the quarterback who takes the first rep to be decided by a literal coin flip before each practice.

This was a very calculated move by Riley and his staff, as not only will the daily competition make both quarterbacks - and everyone else on offense around them - better as a result, it will also give both Lee and O'Brien an equal opportunity to win the job.

That, in turn, should help avoid any bruised egos, as letting them battle it out each day on the field leaves little argument when a final decision on a starter is made.

There's a chance that Nebraska won't officially name its starter until on into fall camp, but the next 15 practices could very well give either Lee or O'Brien a valuable leg up coming out of the spring.

Today marks the official debut of new defensive coordinator Bob Diaco, who alongside the quarterback battle will be one of the biggest storylines of the entire offseason.

Nebraska spent big money to bring Diaco in, and Riley made a very difficult decision to part ways with longtime assistant and friend Mark Banker.

Along with the change comes a shift from Banker's 4-3 base defense to Diaco's 3-4 scheme, which will bring multiple fundamental adjustments at all three levels of the defense.

That's not just for the players, either. The Huskers are also debuting two new defensive assistants in cornerbacks coach Donté Williams and safeties coach Bob Elliott.

How quickly Williams and Elliott as well as returning coaches Trent Bray and John Parrella get on the same page with what Diaco is trying to do will be critical in how quickly the Blackshirts make the transition this offseason.

Nebraska brings back five players who have starting experience along the offensive line, but that doesn't mean the starting unit is already locked into place.

Obviously guys like left tackle Nick Gates, left guard Jerald Foster, and right guard Tanner Farmer are expected to hold down their starting spots, but the competition at center and right tackle will definitely be interesting to watch.

The main candidates at center look to be sophomore Michael Decker and redshirt freshman John Raridon. But if neither of those two does enough to take control this spring, the Huskers could look at shuffling things around and moving a guard inside to join the center battle in the fall.

At right tackle, both senior David Knevel and junior Cole Conrad started games last season. Riley said Knevel would enter spring as the No. 1, but added that Conrad would get ample reps and opportunity with the first-team.

The room for error looks to be very small for Knevel, and whoever wins the job will certainly have earned it with their play this offseason.

Part of the move from a 4-3 to a 3-4 base entailed some players changing up their positions heading into the offseason, especially in the front seven at defensive line and linebacker.

When Riley announced the tentative two-deep depth chart entering spring ball, there were a few interesting moves that caught some attention.

In particular, the inclusion of three former defensive ends at the boundary (or strongside) outside linebacker spot was very intriguing. Alex Davis, Sedrick King, and Ben Stille joined Quayshon Alexander on the announced two-deep.

Riley also announced that former defensive end Collin Miller, who is questionable for spring ball with a toe injury, had moved to inside linebacker.

On the d-line, Mick Stoltenberg was officially confirmed as the No. 1 nose tackle with Khalil Davis backing him up, while Carlos Davis looks to the be the leader at the boundary defensive end spot.

How these moves pay off over the course of the offseason will go a long way in answering how quickly the new defensive scheme finds its footing.

Outside of the loss of safety Nate Gerry, Nebraska returns the rest of its starting secondary from last season.

However, the defensive backfield is far from settled heading into the spring.

At cornerback, senior Chris Jones looks to be primed to return to his starting role as the field (weak side) corner, but he will still get pushed by promising redshirt freshman Dicaprio Bootle.

Senior Joshua Kalu will definitely have his hands full holding off sophomore Lamar Jackson at the boundary corner, as that might be the most competitive position battle on the entire defense.

At safety, Riley raised some eyebrows when he put both returning starters Aaron Williams and Kieron Williams on the free safety two-deep, while junior Antonio Reed and sophomore JoJo Domann will compete at strong safety.

It appears that no job is safe in Nebraska's secondary going into the spring, which should create some serious competition over the next few months.