Pac-12 Conference football underwent some significant changes during the offseason, adding four new coaches and an influx of fast-paced offenses.

The top of the conference still has a familiar look: Southern California in the South, Oregon in the North.

The Ducks never left, really. The Trojans had to fight their way back after some dark days.

Leveled by sanctions that led to the Reggie Bush Heisman Trophy giveback, USC was banned from the postseason the past two seasons and hamstrung by the loss of 30 scholarships over three years.

Postseason eligible again, USC is back, buoyed by the return of quarterback Matt Barkley, a Heisman Trophy favorite, the addition of Penn State leading rusher Silas Redd and 17 returning starters.

The Trojans are not just the favorites to win the Pac-12 South. They are among the front-runners to win the final BCS championship in January.

“We’re two years removed from what was handed down as people saying ‘SC is over,’ and being a preseason No. 1 team two years later is extremely exciting for our university and for our fans,” USC coach Lane Kiffin said.

Oregon had been the Pac-12’s dominant team while the Trojans were pushed out of the spotlight.

The Ducks played for a national championship two years ago and were a contender last season before winning the Rose Bowl for the first time in 95 years.

Oregon must replace running back LaMichael James and quarterback Darron Thomas, but these fast-flying Ducks have plenty of talented replacements ready and are poised for another season in the top 10.

And it’s not just Trojans and Ducks.

They are the ones to beat, for sure. But Stanford and Utah have solid teams, Arizona, Arizona State and UCLA have new coaches, and the always-entertaining Mike Leach takes over at Washington State.

It should be an interesting season.

NORTH

OREGON — Key players: RB Kenjon Barner, RB De’Anthony Thomas, LB Michael Clay, DE Dion Jordan, WR Josh Huff, FS John Boyett. Returning starters: offense 5, defense 7.

Notes: Coach Chip Kelly met with the NFL’s Tampa Bay Buccaneers about their head-coaching opening but decided to stay in Eugene. … The Ducks will have a tight battle to replace Darron Thomas at QB. Sophomore Bryan Bennett passed for 376 yards and six touchdowns while Thomas was hurt last season, but freshman Marcus Mariota looked good in spring and could be a star in the making. … LaMichael James was a Heisman Trophy finalist and an All-American, but Barner and De’Anthony Thomas should make sure Oregon doesn’t miss a fast-stepping beat.

STANFORD — Key players: RB Stepfan Taylor, TE Zach Ertz, LB Chase Thomas, DE Ben Gardner, LB Shane Skov, WR Ty Montgomery. Returning starters: offense 6, defense 7.

Notes: Stanford’s biggest hurdle will be replacing quarterback Andrew Luck, a two-time Heisman Trophy finalist who was the No. 1 overall pick in the NFL draft. Brett Nottingham has a strong arm and was Luck’s backup, but Josh Nunes has impressed the coaches with his game management. … Skov was Stanford’s leading tackler as a sophomore, but he tore a ligament in his left knee the third game of the 2011 season. He will be suspended for the opener against San Jose State after being arrested for DUI last winter. … Taylor ran for more than 1,300 yards last season.

WASHINGTON — Key players: QB Keith Price, CB Desmond Trufant, WR Kasen Williams, TE Austin Seferian-Jenkins, DE Josh Shirley. Returning starters: offense 6, defense 7.

Notes: Coming off the school’s worst statistical defensive season, coach Steve Sarkisian replaced three defensive coaches, including coordinator Nick Holt. New coordinator Justin Wilcox has shifted the Huskies to more of a 3-4 defense, which appeared to free up the defenders in Washington’s spring game. … The Huskies have to replace top running back Chris Polk and have plenty of question marks on the offensive line. … Price was stellar in his first season as a starter, setting a team record by completing 66.9 percent of his passes while throwing for more than 3,000 yards and 33 TDs.

CALIFORNIA — Key players: QB Zach Maynard, RB Isi Sofele, RB C.J. Anderson, WR Keenan Allen, DE Mustafa Jalil, NG Aaron Tipoti. Returning starters: offense 6, defense 6.

Notes: Sofele and Anderson give the Bears a nice 1-2 punch, but the offensive line has holes to fill. … Maynard completed 57 percent of his passes for nearly 3,000 yards, but he had 12 interceptions to go with 17 TDs. … Allen, one of the most dynamic receivers in the conference, underwent ankle surgery in the spring but is expected to be ready for the season opener. … Cal opens remodeled Memorial Stadium against Nevada on Sept. 1.

WASHINGTON STATE — Key players: QB Jeff Tuel, WR Marquess Wilson, WR Dominique Williams, DE Travis Long, S Deone Bucannon, T John Fullington. Returning starters: offense 6, defense 7.

Notes: The Cougars were looking for a fresh start after firing Paul Wulff and got a big one with the hiring of Mike Leach. The former Texas Tech coach is known for his innovative offense and way of doing things, and he has already shaken things up in Pullman. … Tuel labored through injuries last season and Leach has said he will have to compete with Connor Halliday for the starting job this season. … Washington State had a hard time keeping its quarterbacks healthy with an offensive line that ranked among the worst in the country in allowing sacks.

OREGON STATE — Key players: QB Sean Mannion, RB Malcolm Agnew, WR Markus Wheaton, CB Jordan Poyer, DE Scott Crichton, DE Dylan Wynn. Returning starters: offense 8, defense 8.

Notes: This could be an important season for the Beavers and head coach Mike Riley. Oregon State went to the 2009 Las Vegas Bowl but has had consecutive losing seasons, including 3-9 in a 2011 season filled with injuries. … Mannion took over for Ryan Katz as the starter at QB last season but had some growing pains as a redshirt freshman. He passed for 3,332 yards, third-most in school history, and had 16 touchdowns last season, but he also threw 18 interceptions. … Crichton set a school record by forcing six fumbles and Wynn led the nation with five recoveries, also a school record.

SOUTH

SOUTHERN CALIFORNIA — Key players: QB Matt Barkley, WR Robert Woods, S T.J. McDonald, RB Silas Redd, WR Marquis Lee, LB Dion Bailey, CB Nickell Robey. Returning starters: offense 9, defense 8.

Notes: The return of Barkley was a huge boost for the Trojans. Projected as a high NFL draft pick, Barkley made a surprise announcement that he would return for his senior season at Southern Cal. He has matured each season and passed for 3,528 yards and 39 touchdowns with seven interceptions last year. … In case the Trojans didn’t have enough weapons, they added Silas Redd, who rushed for more than 1,200 yards last season at Penn State and will immediately be eligible due to sanctions stemming from the Jerry Sandusky child sex abuse scandal. … Woods is healthy after being hampered by an ankle injury last season and is one of the most dynamic receivers in the country.

UTAH — Key players: RB John White IV, QB Jordan Wynn, DT Star Lotulelei, WR DeVonte Christopher, S Brian Blechen, S Eric Rowe. Returning starters: offense 9, defense 7.

Notes: The Utes had a rough start to their inaugural season in the Pac-12 but finished 8-5 and beat Georgia Tech in overtime in the Sun Bowl. … Wynn missed the first nine games of the 2011 season with a shoulder injury, but he bulked up in the offseason to become durable after two shoulder surgeries in 10 months. … White was the durable one after being a junior college transfer last season, leading the Pac-12 with 316 carries while piling up 1,519 yards and 15 TDs. … Lotulelei is one of the premier defensive linemen in the country, but the Utes have a couple of big holes to fill on the offensive line with the losses of tackles Tony Bergstrom and John Cullen.

UCLA — Key players: RB Johnathan Franklin, WR Joseph Fauria, LB Patrick Larimore, QB Richard Brehaut, QB Kevin Prince. Returning starters: offense 7, defense 8.

Notes: Neither Brehaut nor Prince seemed to be a good fit for former coach Rick Neuheisel’s “pistol” offense, but they will play under a new offensive coordinator in Noel Mazzone, the former O-coordinator at Arizona. … UCLA was either really good or really bad under Neuheisel and is hoping for more consistent results under Jim Mora, the former NFL head coach who hopes to instill more discipline. … UCLA was the Pac-12 South champion last season because rival USC was ineligible for the postseason, and the Bruins finished with a losing record (6-8) after losing to Oregon in the conference championship game and then to Illinois in the Fight Hunger Bowl.

ARIZONA — Key players: QB Matt Scott, RB Ka’Deem Carey, LB Jake Fischer, RB Taimi Tutogi, LB Brian Wagner, S Tra’Mayne Bondurant. Returning starters: offense 6, defense 7.

Notes: The hiring of Rich Rodriguez, the former West Virginia and Michigan coach, has generated a buzz in Tucson. Rodriguez had an acrimonious run in Ann Arbor, but his enthusiasm and go-go-go offense have heated things up for U of A football in the desert. … Scott was once expected to be the starter before becoming the understudy to Nick Foles the past two seasons. He redshirted last season and is looking forward to his chance in the spotlight without having to look over his shoulder. … Carey has a nice combination of speed and power, but he didn’t quite live up to the heralded-freshman hype last season. … Wagner led the nation in tackling last season at Akron before transferring to Arizona.

ARIZONA STATE — Key players: RB Cameron Marshall, RB Jamal Miles, DT Will Sutton, LB Brandon Magee, CB Osahon Irabor. Returning starters: offense 4, defense 4.

Notes: After taking some heat for bolting Pittsburgh after just one season, new head coach Todd Graham has won over Arizona State’s players and its fan base, creating some long-awaited excitement in Tempe. … The biggest decision will be picking a replacement for quarterback Brock Osweiler, who is now in the NFL with the Denver Broncos. Mike Bercovici and Taylor Kelly are competing with highly touted freshman Michael Eubank, but none of the three has started a college game. … Marshall is healthy after a nagging ankle injury hampered him last season. … Magee, back after tearing his Achilles tendon before last season, signed with baseball’s Boston Red Sox but will play for the Sun Devils this season.

COLORADO — Key players: QB Connor Wood, RB Tony Jones, T David Bakhtiari, DT Will Pericak, LB Doug Rippy, S Ray Polk. Returning starters: offense 3, defense 6.

Notes: The Buffaloes had a rough initiation into the expanded Pac-12, going 3-10, and could be in for some more difficult times this season with one of the youngest teams in the nation. … Wood is the likely front-runner to start at QB after sophomore Nick Hirschman broke his foot for the second time in less than a year last March. … Paul Richardson, one of Colorado’s top returning receivers, is out for the season after tearing his ACL in the spring. … The Buffaloes struggled last season, but they did manage to end a 23-game road losing streak.

Coming next week

Preseason football practices get under way Monday for the Oregon Ducks and the Oregon State Beavers, and the Bulletin will have reports from both camps. Watch for our season preview of the Ducks on Tuesday and our look ahead for the Beavers on Wednesday.