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

We move on to the defensive line, starting with the South Division.

Arizona: The Wildcats are expecting -- hoping strongly -- that end Reggie Gilbert will be granted a fifth year due to injury hardship. He's practicing this spring in anticipation of the NCAA doing the right thing. That would mean two of three starters will return, with Parker Zellers also back at nose tackle along with Jeff Worthy. Touted juco transfer Anthony Fotu is a good bet to replace Dan Pettinato at the other end. Pettinato, in fact, is the only player gone from the late-season depth chart, but there is an expectation some youngsters will immediately compete for playing time in the fall.

Arizona State: The Sun Devils welcome back just about every player from their late-season depth chart, other than end Marcus Hardison, though he was the unit's most productive lineman. Tashon Smallwood, Edmond Boateng and Demetrius Cherry offer experience -- 63 combined tackles last season -- and there's also massive Mo Latu as an interior option. Further, there's a chance nose tackle Jaxon Hood, who has been dealing with personal issues, could return in the fall.

Colorado: The Buffaloes welcome back three of four starters, only needing to replace tackle Juda Parker, while there are newcomers -- some with familiar faces -- also in the mix. Further, the Buffaloes, with new coordinator Jim Leavitt, could use more 3-4 looks in the fall. Returning starters are ends Derek McCartney and Jimmie Gilbert and tackle Josh Tupou, though Tupou was arrested after an off-campus brawl last week so his status might be questionable. Samson Kafovalu is back after sitting out a year, and he was listed as a starter at defensive tackle on the post-spring depth chart. When he gets healthy, end Tyler Henington will be in the mix. Two junior college transfers, end Blake Robbins and tackle Jordan Carrell, participated in spring practices, as did "grayshirt" Leo Jackson (6-foot-3, 285 pounds).

UCLA: The Bruins lose defensive end Owamagbe Odighizuwa, a second-team All-Pac-12 performer in 2014, but they welcome back second-team all-conference nose tackle Kenny Clark and end Eddie Vanderdoes, and it says here having a pair of athletic 300-pounders who are multi-year starters up front is typically a good thing. Jim Mora has said a lot of nice things about junior juco transfer Takkarist McKinley, who is the favorite to replace Odighizuwa. He had 2.5 sacks in limited action last season. True sophomores Jacob Tuioti-Mariner and Matt Dickerson offer depth outside -- both have pass-rushing potential -- while Eli Ankou figures to back up Clark.

USC: No team in the country is replacing a better defensive end than Leonard Williams, but the Trojans do welcome back some experience here, including two of three starters and experienced rush end Scott Felix. Antwaun Woods is back at nose tackle, though he is sitting out the spring with an injury, and there's good depth with Cody Temple and Kenny Bigelow, who missed last season with a knee injury. Devon Simmons and Claude Pelon, a pair of 295-pounders, are the likely starters at the ends. Redshirt freshman Malik Dorton and junior Jeff Miller offer smaller, quicker options on the outside, and Greg Townsend is another option. It's also possible linebacker Jabari Ruffin could get at look at defensive end when he's healthy, and it's likely one or two of the touted incoming freshmen will be the rotation.

Utah: John Pease came out of retirement to replace coordinator Kalani Sitake and coach the Utes' defensive line, but that doesn't likely mean much in terms of schematic changes up front. While there's a significant void left behind by All-American end Nate Orchard, two of four starters and plenty of experience are back, including end Hunter Dimick, who had 10 sacks in 2014 as Robin to Orchard's Batman. Inside, there's Lowell Lotulelei (younger brother of Star who flashed plenty of potential as a freshman), Filipo Mokofisi, Viliseni Fauonuku, Stevie Tu'ikolovatu and Clint Shepard. Replacing Orchard is less certain. Pita Taumoepenu was Orchard's backup last season and he finished with 4.5 sacks. Another option is Jason Fanaika, while UCLA transfer Kylie Fitts and Wallace Gonzalez also should be in the mix.