With spring practice underway at many Pac-12 destinations, it's time to do our annual position-by-position breakdown.

Today, we move to the defensive side of the ball and we're starting with the defensive backs. For the sake of time and avoiding headaches, we're going to just separate this into three groups -- the defensive backs, linebackers and defensive line. For teams that have certain hybrid positions and players, we put them into which of those three categories we thought they best fit. If you don't like how we did it, feel free to complain here.

UCLA: The Bruins' secondary will miss the versatility of Anthony Jefferson (72 tackles, 3 TFL, 1 interception, 8 pass break ups), but UCLA has some good talent and depth built up, too. The Bruins return starting corners Ishmael Adams and Fabian Moreau, as well as both of their back ups in Priest Willis and Marcus Rios. Adams and Moreau were both top-10 tacklers for the Bruins last season, but it’d be nice to see both play a bit more consistently, specifically Moreau, who really stepped up at the end of last season. But, that’s what the spring is for -- getting back to those basics and learning to play better as a unit consistently. It gets interesting at safety for the Bruins where they have Tahaan Goodman, who stepped in for Randall Goforth last season and finished with 46 tackles, and Jaleel Wadood, who had a fantastic freshman season, finishing as the Bruins’ fifth-leading tackler. Those two could be the lead candidates for starters but don’t count out Randall Goforth, coming off surgery on both shoulders, who’s expected to be back though Jim Mora hasn’t given any official word on him yet.

USC: Let’s start with the corners, where the Trojans are in excellent shape, returning both Adoree’ Jackson (who would like to win the Thorpe and Heisman at USC) and Kevon Seymour. Both Jackson and Seymour finished last season with 49 tackles apiece, and with the starting spots basically locked down, Steve Sarkisian will probably spend the spring looking at the options behind them. Expect Chris Hawkins, Jonathan Lockett and Lamont Simmons to get the most run here.

Both Hawkins and Lockett have taken reps at safety this spring, too, but that’s more to build depth than anything else since the Trojans return both John Plattenberg and Leon McQuay III. Earlier this month USC defensive coordinator Justin Wilcox said that this is a big spring for McQuay and we expect the same is true for Plattenberg, as both need to prove they can play consistently at a high level. Plattenberg started six of the Trojans’ final seven games -- half at free safety and the other half at strong safety -- so he needs to keep that momentum moving forward. These two seem pretty sure bets as the two top safeties coming into the fall but they’ve got to do more than prove they’ll be the best out of spring practice. With stud safeties Marvell Tell’s and Ykili Ross’ enrollments on the horizon, Plattenberg and McQuay need to be as many steps ahead as possible in order to keep those starting spots next fall.

Utah: With as much nickel as the Utes played last season, they’ll want a lot of competition in the secondary this spring as they look to replace Davion Orphey, Eric Rowe and Brian Blechen. Dominique Hatfield will enter the spring as a near lock for one of the corner spots after finishing with 38 tackles, one interception (which was a pretty important interception) and nine pass break ups last season. The other front-runner for a starting spot would be Justin Thomas at nickel. He tallied 37 tackles and one sack in 2014. Opposite Hatfield, the other cornerback spot will be fun to watch as Ahmad Christian, Tavaris Williams and Boobie Hobbs battle it out (with Thomas playing a factor as well). Cory Butler, the No. 2 juco corner in the ESPN JC 50, won’t be here this spring so other players need to try and get a leg up on a kid who looks like he could be an instant contributor.

At safety the Utes get a boost with the return of Tevin Carter, who was granted a medical hardship for last season. Competing with him at safety will be Marcus Williams, the player who filled in for him in his absence. Those two will be joined by Jason Thompson (who came over from quarterback, because that position group certainly has enough competition as is), Andre Godfrey and Austin Lee, which gives the Utes some pretty good competition at safety.