The countdown clock hanging inside the South Dakota football locker room is down to 151 days.

A photograph of the Coyotes’ motivational time-keeping mechanism was posted recently on Twitter, including the sign below the numerals which reads: Beat Oregon.

Hope springs eternal in Vermillion, S.D.

More than 1,700 miles away in Eugene, there are lofty national expectations for the 2014 Ducks.

Mark Helfrich’s second Oregon team begins on-field preparations for the season, which opens Aug. 30 against South Dakota, on Tuesday with the first of 15 spring practices.

The coaching staff went through a quality control process during the winter to identify areas where the program can improve after an 11-2 season.

“Obviously we need to do some things better up front offensively and we need to do some things better up front defensively,” Helfrich noted. “There’s going to be some roles to fill at receiver. There’s going to be some roles defensively in a lot of places.”

Here are 10 noteworthy story lines entering Oregon’s spring practices, which conclude with the spring game on May 3:

1. The franchise quarterback

There are coaches in important new roles and plenty of key position battles to monitor, but the return of Marcus Mariota makes Oregon one of the favorites to participate in the first College Football Playoff.

Mariota completed 63.5 percent of his passes for 3,665 yards, 31 touchdowns and four interceptions last season as a third-year sophomore. He also ran for 715 yards and nine touchdowns.

If not for a torn MCL sustained against UCLA on Oct. 26, Mariota would have remained on the short list for the Heisman Trophy and may have led the Ducks to a fifth consecutive BCS bowl appearance.

Instead, Oregon finished 2-2 in November as Mariota gritted through the injury. After the season, the humble star announced his decision to return to finish his degree and the business of getting the program back in the national title hunt.

Helfrich said Mariota, who would have been a candidate to be the No. 1 overall pick in this year’s draft had he left for the NFL, took his leadership to a new level during the offseason strength and conditioning program. Now No. 8 is looking to take his game and the Ducks to new heights.

2. The defensive Don

Don Pellum, Oregon’s longtime linebackers coach, replaces the retired Nick Aliotti as defensive coordinator.

It will be interesting to see if Pellum can build on Aliotti’s remarkable run during this golden era.

Pellum said he will stress discipline and fundamentals while doing his best to solve the Stanford problem. Oregon was pushed around at the point of attack against the Cardinal and again during the loss at Arizona.

The primary defensive scheme will remain a 3-4. Pellum, who must replace experienced and productive players on the defensive line and in the secondary, planned to visit peers at other colleges and in the NFL seeking new wrinkles to add to Oregon’s philosophy this spring.

Fans will get a chance to sneak a peek at Pellum’s defense during the spring game at Autzen Stadium, which will be televised by the Pac-12 Network.

3. Push it real good

Pellum acknowledged that Oregon’s defensive line will have to start pushing the pile the other way in order to beat Stanford, which has won back-to-back Pac-12 championships after knocking the Ducks off the national championship path.

The task won’t be easy with the graduation of Taylor Hart, Wade Keliikipi and Ricky Heimuli. However, there are some emerging stars up front in Arik Armstead and DeForest Buckner.

Oregon, which finished sixth in the Pac-12 in rushing defense, has enough depth to piece together formidable rotations up front. Alex Balducci, T.J. Daniel, Stetzon Bair, Sam Kamp and Tui Talia are some of the players vying for major roles.

The nation will learn a lot about the Ducks’ defensive line on Sept. 6 when Michigan State visits Autzen Stadium.

4. Mariota’s go-to-guy

When the Civil War was on the brink of a historic upset, Mariota looked to Josh Huff to save the day for the Ducks.

Bralon Addison certainly has the skill and swagger to take the baton from Huff and emerge as a clutch receiver. During an explosive sophomore season he finished with 890 yards receiving and seven touchdowns.

Steady starter Keanon Lowe also returns this fall. Another familiar face returns to the fold in Dwayne Stanford. The 6-5, 197-pound redshirt sophomore will be a tantalizing target for Mariota after sitting out last season to recover from a knee injury.

Chance Allen, Jalen Brown, Darren Carrington and B.J. Kelley add to what Helfrich believes is the deepest and most physically gifted crop of receivers Oregon has had since he arrived as Chip Kelly’s offensive coordinator in 2009.

The Ducks are loaded with quality players at tight end with Pharaoh Brown, Johnny Mundt and Evan Baylis all getting meaningful experience last season.

5. Help for Ifo island

Typically, losing three outstanding starters in the secondary would be a major concern for a team, especially in the Pac-12. The fact that lone returning starter is all-American Ifo Ekpre-Olomu still makes cornerback a position of strength at Oregon.

Secondary coach John Neal, considered one of the best in the business, has groomed candidates to replace graduated safeties Brian Jackson and Avery Patterson, as well as cornerback Terrance Mitchell, who left his final year of eligibility on the table for a shot at the NFL.

Dior Mathis and Troy Hill are the next men up at cornerback with Erick Dargan in position to fill Patterson’s shoes. Issac Dixon, Dominique Harrison, Chris Seisay, Tyree Robinson and Reggie Daniels will have a chance to audition for lead roles on the 2014 defense this spring.

6. In case of emergency

Even though Mariota could barely walk leading up to the loss at Stanford last season, the injured star was still deemed to be the team’s best option at quarterback that fateful Thursday night.

It’s time for reserve co-pilots Jake Rodrigues and Jeff Lockie, now redshirt sophomores entering their third spring in the program, to prove to the coaches they can lead the Ducks to victory in the fall.

After a redshirt season, Damion Hobbs will also be in the mix for the No. 2 spot. The returnees will have a head start on incoming freshman Morgan Mahalak, who will be eying the starting gig in 2015 after serving as an understudy to Mariota this year.

7. New sack attack

Oregon’s players were excited when Helfrich added Erik Chinander, a former intern and graduate assistant in the program, to the staff after he spent last year working for Kelly with the Philadelphia Eagles.

Chinander, 34, will bring some youthful enthusiasm to the defense, which will be needed to help fill the void without the fiery Aliotti coaching the outside linebacker/defensive end position group.

The Ducks return senior Tony Washington, who led the team with 7 1/2 sacks and 12 tackles for loss last season. Chinander is also familiar with potential starter Tyson Coleman and eager to develop younger players like Torrodney Prevot.

8. Who DAT?

Oregon’s rushing attack, which led the Pac-12 again last season, is in great shape with the return of Byron Marshall and Thomas Tyner, who combined for 1,749 yards and 23 touchdowns in 2013.

The Ducks will have to replace De’Anthony Thomas, the dynamic running back who averaged 135.3 all-purpose yards per game last season before taking his talents to the NFL draft.

Marshall rushed for more than 1,000 yards as the steady starter last season, and Tyner showed flashes of greatness as a true freshman. Incoming freshman Royce Freeman is a bigger back who could help move the chains in short-yardage situations and punch the ball across the goal-line in the red zone.

Thomas’ all-around versatility will be missed.

9. Just for kicks

Oregon announced last week that Dylan Ausherman, who redshirted last season after transferring into the program from the College of the Sequoias, has left the program. With the graduation of Alejandro Maldonado, that leaves the Ducks with one true punter on the roster — Ian Wheeler.

Offensive coordinator Scott Frost doesn’t plan to punt very often with Mariota and a loaded lineup back. Wheeler, a redshirt freshman, will still have to prove he can handle the duties when called upon.

Matt Wogan, who eventually beat Maldonado out for the place-kicking duties as a true freshman, will look to build on a solid performance in the Alamo Bowl when he made three field goals and three extra points in the Ducks’ 30-7 victory against Texas in San Antonio.

10. Protecting the blindside

Oregon returns all five starters on the offensive line, including all-American center Hroniss Grasu, but left tackle Tyler Johnstone will not participate in spring practices while continuing to recover from a torn ACL sustained during the Alamo Bowl.

Andre Yruretagoyena and Matt Pierson will get the first crack at filling in on the first-team offense in Johnstone’s absence. This spring will also be an opportunity for junior college transfer Haniteli Lousi to challenge incumbent Hamani Stevens at left guard.

Right guard Cameron Hunt was an important part of the rotation last year as a true freshmen. Now his highly touted classmates — Doug Brenner, Elijah George, Jake Pisarcik and Evan Voeller — will have their opportunity to play after redshirting.

Mariota is the face of the program right now, but Oregon is loaded with established Pac-12 standouts and an intriguing mix of young players and newcomers. That countdown clock can’t move fast enough for many Duck fans.

“Obviously, you need to get better at blocking and tackling and fundamental football with your guys on campus. Particularly the redshirt guys that got a great group of practices with bowl prep,” Helfrich said. “You see a lot of progress with those guys usually right away in spring ball of, ‘OK, wow, this guy has had a great offseason and he’s ready to go.’ Or, ‘Shoot, we might not be able to count on that guy for another year.’

“You just kind of keep pushing in all aspects.”

Follow Ryan on Twitter @rgduckfootball . Email ryan.thorburn@registerguard.com .