Spring has sprung, which means every team can show you hope in a handful of grass -- real or artificial.

Some Pac-12 teams have already started, such as Colorado and Stanford, and others begin this week, such as Arizona, Oregon State and USC. Others start later.

But it feels like the right time to take a look at 10 burning issues in the conference. Please keep your hands clear of this post, as it is sizzling hot.

1. Life after Marcus Mariota at Oregon: You might recall Oregon's quarterback over the past three years was a pretty fair player. But Mariota is off to the NFL, where he's sure to get blinged up, buy four Bentleys and start giving everyone alternating left-right cheek air kisses. That leaves the Ducks with a vacancy behind center. While many -- including a few of my esteemed Pac-12 blog associates -- believe Eastern Washington transfer Vernon Adams is almost certain to take over when he arrives in the fall, you all know I am an inveterate party pooper, so I'm skeptical the transition to an FCS QB, albeit a very good one, will be all rainbows and puppy dogs. So what happens this spring, pre-Adams, should have a high degree of relevance for the ensuing fall competition. That means Jeff Lockie and Morgan Mahalak or someone else has an opportunity to throw down the gauntlet and stake a strong claim to the job.

2. Gary Andersen takes over at Oregon State: Mike Riley started the 2014 season as the dean of Pac-12 coaches. Stanford coach David Shaw went so far as to call him the Godfather, which showed Shaw was once a reader of the Pac-12 blog's "Best case-worst case" stories. Riley, however, will begin the 2015 season at Nebraska, a stunning development that is, well, still a bit stunning. Enter Andersen, who's hiring away from Big Ten power Wisconsin was almost as much of a stunner. That means the Beavers, the only Pac-12 team to change head coaches, will be installing new systems on both sides of the ball, as well as getting to know a new coaching staff. Andersen certainly will want to get past the "Hello, my name is..." phase as quickly as possible.

3. USC returns returns to national relevance? The first issue here is whether this deserved a question mark or a period, because the Trojans are fairly certain to begin the 2015 season ranked in the top 10. That means they start the season nationally relevant, period. The question mark, though, concerns whether they can sustain that elevation as they move beyond crippling NCAA sanctions with an impressive roster and improving depth. One might recall it wasn't too long ago when the program's "Unfinished Business" campaign flopped. Second-year coach Steve Sarkisian will be under not inconsiderable pressure to make sure he doesn't suffer through a Lane Kiffin redo.

4. UCLA replaces Brett Hundley: UCLA has 18 starters and a number of other contributors coming back from a team that won 10 games last season and finished ranked 10th. That makes you wonder if perhaps the wrong L.A. team is getting hyped. Ah, but the Bruins are replacing Hundley, a three-year starter who is on the short list of best QBs in program history. While it seems like more than a few folks -- NFL sorts, mostly -- are picking apart Hundley's game of late, what should stand out is how often he delivered for the Bruins, including a troika of wins over That Team From Downtown. Further, this is an interesting battle between a scrappy veteran with a familiar last name in junior Jerry Neuheisel, and a brash, touted true freshman in Josh Rosen, who entered school early with the anticipation of taking over for Hundley. It will be interesting to see if any pecking order develops this spring or if coaches drop an "or" between them on the depth chart. Oh, wait. UCLA is the only Pac-12 that doesn't publish a depth chart. Never mind.

5. Oregon State replaces Sean Mannion: Mannion and the Beavers didn't have a great 2014, but you don't say goodbye to a four-year starter with 83 career touchdown passes lightly and without some sense of transition, particularly when there's also a new coaching staff on hand. Things appear to be wide open between Luke Del Rio -- Mannion's backup -- Brent VanderVeen, Kyle Kempt, Marcus McMaryion, Nick Mitchell, etc. (There are seven QBs on the roster.) It seems reasonable to believe Andersen will want to winnow that list down to around three guys by the end of spring.

6. Washington's no-name defense{ The Huskies say goodbye to six defensive starters, including three -- linebackers Shaq Thompson and Hau'oli Kikaha and defensive tackle Danny Shelton -- who were first-team All-Pac-12 and earned All-American honors. All three are expected to be early picks in the NFL draft, so the talent drain is legitimate, not just a system thing. The only returning defender who earned any type of postseason recognition is true sophomore safety Budda Baker, who was honorable mention All-Pac-12 and has huge upside. That's a good start, but it's unlikely the Huskies will be able to replace these mainstays' production with typical depth-chart promotions. If the Huskies' defense is going to equal or, perhaps, exceed its 2014 numbers, it's going to have to play better as a team, which will be a key test of the second-year coaching staff led by coordinator Pete Kwiatkowski.

7. Getting coordinated: Oregon State had the only coaching change at the top, which included new coordinators on both sides of the ball, but four other teams have changed defensive coordinators and Utah replaced both coordinators, who both bolted for other jobs. Utes coach Kyle Whittingham went the familiar face route, promoting Aaron Roderick from within on offense to replace Dave Christensen, now at Texas A&M, and bringing John Pease out of retirement to replace longtime defensive coordinator Kalani Sitake, who joined Andersen at Oregon State. Colorado pushed aside defensive coordinator Kent Baer, who left for UNLV, and hired former South Florida head coach Jim Leavitt, a major coup for the Buffs. UCLA replaced Jeff Ulbrich, who departed for a job with the Atlanta Falcons, with former Penn State defensive coordinator Tom Bradley, who was at West Virginia in 2014. Washington State fired Mike Breske and replaced him with Alex Grinch, a defensive backs coach at Missouri last year. That's a pretty significant amount of turnover on one side of the ball, which will make life more interesting for the conference's offensive minds, particularly early in the season.

8. Stanford rebuilds defense: Speaking of defense, the conference's best unit over the past five years is replacing seven starters, including all of its D-linemen and three of four starters in the secondary. Further, a number of injuries, most notably to D-lineman Aziz Shittu and cornerback Ronnie Harris, will muddy the waters this spring. While it seems unlikely the bottom will fall out for the Cardinal -- there's plenty of promising youngsters on hand -- it's difficult to believe this won't be a transitional season on the mean side of the ball.

9. California dreaming? Cal has 17 starters back, second most in the conference and among the most in the nation, from a team that seemed to turn a corner in 2014 in Year 2 under Sonny Dykes. That crew includes quarterback Jared Goff, an NFL prospect who could make a star turn this fall if the Bears start to win. The offense, which averaged 38 points per game last season, should be good. The question is defense. That unit improved its points surrendered total by nearly a TD from 2013 to 2014, but that still ended up ranked last in the Pac-12 at 39.8 points per game. The Bears might be good enough to become bowl eligible with a defense that is only slightly better. But if they want to take a decisive step forward in the North Division, they need to at least find a way to be mediocre on defense.

10. Next-step QBs: Last season, the Pac-12 featured a glittering group of returning starting quarterbacks led by Mariota, Hundley, Mannion and Arizona State's Taylor Kelly. This year, seven teams welcome back established QBs, but the list is far less scintillating, while a couple other teams have decided front-runners at the position, most notably Mike Bercovici at Arizona State. USC's Cody Kessler leads the bunch, but he has to show he can win big games. Goff is a candidate for all-conference honors, and Stanford's Kevin Hogan finished strong last season after muddling through the first three-fourths of the season. Arizona's Anu Solomon and Colorado's Sefo Liufau are trying to take the proverbial next step, while Utah's Travis Wilson wants to show he should be a four-year starter this spring with Kendal Thompson out with an injury. Washington's returning starter, Cyler Miles, figures to face a tough challenge this spring to retain his job, while Washington State's Luke Falk wants to build on the mostly solid job he did after replacing Connor Halliday.