All eyes on quarterback competition as USC opens spring football practice

The date has been circled on calendars for almost two years. On Sept. 3 at AT&T Stadium in Arlington, Texas, USC will open the season against defending national champion Alabama.

The Trojans best be prepared.

Coming off yet another year of turmoil, USC will begin working toward the coming season in 15 spring practices starting Tuesday.

For the first time in three years, the sessions will feature competition among quarterbacks to become the starter.

Fourth-year junior Max Browne or redshirt freshman Sam Darnold will replace departed three-year starter Cody Kessler.

The Trojans finished 8-6 last season after Steve Sarkisian was fired as coach after five games.

Clayton Helton took over as interim coach and led USC to the Pac-12 Conference championship game, where the Trojans lost to Stanford before losing to Wisconsin in the Holiday Bowl after Helton was named permanent coach.

Helton said after the season that the “No. 1 priority” this spring would be to develop “physicality in the trenches.”

But at USC, it’s always about the quarterback.

Browne, 6 feet 5 and 220 pounds, spent the last two seasons as a seldom-used backup. But he has spent three seasons working closely with Helton — who had been the quarterbacks coach — and is the favorite to win the job.

Darnold, 6-4 and 215 pounds, turned heads during his first fall camp last season. He’s mobile and has the ability to push the competition into the fall, when he could possibly win the job.

Several starters are expected to sit out or will be limited in spring ball as they recover from injuries. Another, three-way standout Adoree’ Jackson, has been excused as he competes in track and field, with the hope of qualifying for the Olympics in the long jump.

Here are some questions facing the Trojans heading into the spring:

::

Who are the quarterback candidates and when will Helton announce a starter?

Browne is the favorite, Darnold is the main challenger and Jalen Greene and Matt Fink will be in the mix, at least for awhile.

Browne was the five-star centerpiece of USC’s 2013 recruiting class but was stuck behind Kessler. Last season, he completed eight of 12 passes for 113 yards.

Darnold’s mobility makes him a different type of Trojans quarterback. As a senior at San Clemente High, he passed for 2,996 yards and 39 touchdowns, with eight interceptions, and rushed for 785 yards and 13 touchdowns.

Greene switched to receiver last season, but Helton said he would be at quarterback this spring. Greene, used in double pass plays initiated by Kessler, completed three of four passes for 127 yards and a touchdown.

Fink, from Glendora High, enrolled in January and is a candidate to redshirt.

Helton said he probably would not name a starter until the end of spring or in the fall.

::

Who will replace the starters on the defensive line?

Next to quarterback, this is the biggest question facing the Trojans. Coordinator Clancy Pendergast is expected to implement a 5-2 defense and three starters must be replaced.

Noah Jefferson, 6-6 and 300 pounds, and Rasheem Green, 6-5 and 285, played in every game as freshmen last season. Kenny Bigelow, a fourth-year junior, made three sacks last season and will have a chance to make the starting lineup, along with third-year sophomore Malik Dorton, sophomore Jacob Daniel and redshirt freshmen Christian Rector and Kevin Scott.

Freshman Liam Jimmons, who enrolled in January, has joined the competition.

::

What is happening at linebacker?

Pendergast’s new scheme changes things. Two linebackers will move up front along the line and two will stay back.

Jabari Ruffin, Porter Gustin, Osa Masina, Don Hill, John Houston, Christian Rector and January enrollee Oluwole Betiku are candidates to start at defensive end.

The status of fifth-year senior Scott Felix is uncertain because of a personal issue, according to USC.

At inside linebacker, Anthony Sarao completed his eligibility and Cameron Smith will be limited this spring as he returns from a knee injury and shoulder sprain.

Michael Hutchings, Olajuwon Tucker, Uchenna Nwosu and Quinton Powell will compete at the position.

::

Who will man the offensive line?

Injuries plagued the line last season. Center Max Tuerk suffered a season-ending knee injury and, a short time later, so did Toa Lobendahn, who had moved from guard to replace Tuerk.

Tuerk graduated and Lobendahn will be sidelined this spring as he continues to rehabilitate his knee, but he is scheduled to return in the fall.

Starting right tackle Zach Banner returns, as does left tackle Chad Wheeler, who did not travel with the team to the Holiday Bowl after he was involved in an incident with police.

Guards Damien Mama and Viane Talamaivao have two seasons of experience.

The big question is at center. Khaliel Rodgers started five games before he was sidelined and slowed because of shoulder injuries. Nico Falah started one game.

::

Who is coaching what?

Helton promoted Tee Martin from receivers coach to offensive coordinator and Johnny Nansen has moved from tailbacks to linebackers coach.

Pendergast, Tommie Robinson and John Baxter return to the staff after they were let go by Sarkisian after the 2013 season. All three are in their previous posts: Pendergast is the defensive coordinator; Robinson will coach tailbacks; and Baxter will handle special teams and tight ends.

Neil Callaway and Tyson Helton, Clay Helton’s younger brother, join the staff from Western Kentucky. Callaway will coach the offensive line and Tyson Helton will take over his brother’s former position as quarterbacks coach.

Former USC All-American and first-round NFL draft pick Kenechi Udeze will make the jump from his role last season as assistant strength and conditioning coach to the defensive line.

After three seasons as Louisiana Tech’s defensive backs coach, Ronnie Bradford will handle the same duties with the Trojans.

sports@latimes.com