Colorado gets an early -- and chilly? -- start to spring practices Monday, leading the Pac-12 out of the gate.

Not to be caught off guard, here are five major issues confronting the North Division as spring practices begin.

Here's what we had to say about the South.

1. Oregon post-Mariota: The Ducks are not only replacing their quarterback, they are replacing the best player in program history. Heck, Marcus Mariota, the 2014 Heisman Trophy winner, is one of the greatest players in Pac-12 history. Oregon was good before Mariota and will be good after him. Still, he's been behind center for three years, so this is a significant transition. Further, with many suspecting the starting job is Eastern Washington transfer Vernon Adams' to lose, and he won't arrive until the summer, that means the establishment of a post-spring pecking order won't even approach an endgame. The guy with the most at stake is junior Jeff Lockie, Mariota's backup the past two years. He needs to make a strong statement with his play and leadership. If he does, it could give him a meaningful advantage when Adams arrives.

2. QB questions: The Ducks aren't the only North team uncertain at QB. In fact, only California with Jared Goff and Stanford with Kevin Hogan are set 100 percent behind center. Oregon State is replacing Sean Mannion in what figures to be a wide-open competition, one made more wide open by the departure of Mike Riley and arrival of Gary Andersen. While Washington has a returning starter in Cyler Miles, he was inconsistent in 2014 and could face a challenge from K.J. Carta-Samuels and touted true freshman early arrival Jake Browning. At Washington State, Luke Falk did a good job stepping in for an injured Connor Halliday -- he's certainly the front-runner to win the job -- but Mike Leach isn't going to hand him the starting spot by any means.

3. A new sheriff in Corvallis: Riley shocked just about everyone when he bolted for Nebraska after 14 seasons -- including the last 12 -- leading the Beavers. It wasn't an overwhelmingly sad departure, though, as more than a few Beavers fans had grown frustrated with the recent state of the program, particularly when compared to rival Oregon. The hiring of Andersen away from Wisconsin also seemed like a bold move, one that generated plenty of enthusiasm among the boosters. But Andersen will be adopting new schemes on both sides of the ball with a roster full of uncertainty. With a getting-to-know-you phase, spring will be much different in Corvallis this year.

4. Getting defensive: The biggest difference between the Pac-12 North and South divisions heading into spring is defensive turnover and/or questions. The South welcomes back a lot of defensive starters, while the North doesn't. Oregon State has just two defensive starters coming back and Stanford has just four. While Washington has six, it also loses three first-team All-Pac-12 performers in LB Shaq Thompson, OLB/DE Hau'oli Kikaha and DT Danny Shelton. Oregon has seven coming back, but it's rebuilding its secondary and replacing end Arik Armstead. Washington State has nine starters returning but it has a new coordinator in Alex Grinch after Mike Breske was fired. Cal has eight starters coming back, but it played lousy defense in 2014, ranking last in the conference with 39.8 points per game. North defenses figure to get a lot of attention this spring.

5. Year 2 for Chris Petersen: Perhaps the Pac-12's biggest story last spring was the arrival of Petersen, who was lured away from a celebrated run at Boise State to replace Steve Sarkisian, who bolted for USC. Petersen inherited a team that looked talented enough to make a run at the North title, or at least make a legitimate challenge to the Oregon-Stanford domination. It didn't come to pass. The Huskies were inconsistent on both sides of the ball, particularly on offense, and finished a lackluster 8-6 after a rotten performance in the TicketCity Cactus Bowl against Oklahoma State. The 2015 Huskies have just 12 position-player starters returning, so they will have many depth-chart questions to address this spring. On the plus side, there should be a good deal of familiarity between players and coaches, both in terms of scheme and approach. This looks like a year of transition for the program, but Huskies fans will be looking for signs of growth under Petersen that would suggest good things happening in the future.