For the week leading up to Duke football's 2013 Spring Game, the Blue Zone will be breaking down this year's returning squad unit by unit to examine the key changes you'll see for next year's Blue Devils. Today, we start with the quarterbacks.

Redshirt sophomore Anthony Boone is poised to take over the starting quarterback job for Duke (Photo by Thanh-Ha Nguyen/The Chronicle).

UPDATE: Since this post was published, redshirt freshman quarterback Thomas Sirk underwent surgery to repair a ruptured achilles, an injury that will likely cost him the entire 2013 season. He will no longer compete for snaps at quarterback, and Anthony Boone will be the undisputed No. 1 starter. Redshirt junior Brandon Connette will move up to No. 2 on the depth chart and true freshman Parker Boehme will likely be the emergency quarterback.

Key returners: redshirt junior Anthony Boone, redshirt junior Brandon Connette

Key departures: Sean Renfree

Now in the mix: redshirt freshman Thomas Sirk, freshman Parker Boehme

2012 performance: Last season, this was Sean Renfree's team. With their once-reliable general now graduated, this team will look for new leadership.

Assuming the role of starting quarterback for more than three seasons at Duke, Renfree was a stalwart under center for the Blue Devils. Completing 66.3 percent of his passes for 2,755 yards, 18 touchdowns and just eight interceptions during his final collegiate season, Renfree was about as dependable a passer as there was in the ACC. His only downfall last year was that he struggled to stay on the field. Renfree took some crushing hits throughout the season and was knocked out of multiple games in 2012. This opened the door for backup Anthony Boone, who stepped in during Renfree's absence and performed admirably, leading the team to a fourth-quarter victory against Wake Forest and starting Duke's next contest against Virginia, when Boone threw a career-high four touchdown passes.

Boone finished the season with 531 yards through the air, five touchdowns and just two picks. He struggled with his accuracy in the short and intermediate passing games, however, completing just 51.6 percent of his throws on the season. The mobile Boone's abilities as a dual-threat quarterback allowed head coach David Cutcliffe to use him in packages even when Renfree was healthy. When it was all said and done, Boone appeared in 11 games for Duke last year.

Connette continues to be listed as a quarterback, though he rarely throws the ball. Cutcliffe experimented with Connette all over the field last season, calling him Duke's "phantom." After utilizing Connette as a quarterback, running back, tight end, wide receiver and free safety last season, the head coach said he expects Connette's versatile role on the team to only expand next season. Cutcliffe loves Connette's athleticism and natural abilities at a variety of positions. He threw the ball sparingly last season—completing three short-yardage touchdown passes to tight end David Reeves on the year—but was effective as both a short-yardage runner and a receiving target.

Boehme enrolled early as a true freshman, but has been limited in spring practice after having surgery shortly after his arrival to Durham. The Florida native was also lauded for his ability as a dual-threat quarterback in high school, but will not play a heavy factor in Duke's quarterback discussion this season.

Season outlook: As of now, Boone is Duke's undisputed No. 1 quarterback heading into next season. He will be backed up by Sirk, who redshirted during his freshman campaign, while Connette will continue to line up under center situationally. Cutcliffe hinted at the possibility of making the starting quarterback job an open competition during training camp, but as of now, the job is squarely Boone's. Duke's quarterback change is one of the most intriguing storylines surrounding the 2013 season. Boone has had opportunities to prove himself during his years here, and while he has had limited success he surely has not excelled either. It will be safe to say that quarterback play will be one of the keys to determining Duke's fate on the gridiron next season.

Boone exhibits superior arm strength to Renfree, which should lend itself well to a dynamic cast of young receivers he will have at his disposal this season, including junior wide receiver Jamison Crowder. At the same time, his accuracy has been troubling in the past, and could be a cause for concern. Cutcliffe likes Boone's abilities as a runner as well, and could use that to implement a more run-heavy scheme next season. Boone has said that Duke will use a stable of returning running backs in a lot of zone-read looks next season, which is far different from the spread-out, vertical passing offense the Blue Devils thrived on in 2012. Boone certainly seems to have approached this offseason with a new focus and has relished in being one of the leaders of this team. Duke hopes that it will see Boone make a jump to the next level this summer—if the Blue Devils do, their transition from 2012 to 2013 could be seamless on the offensive side of the ball.

Sirk is also a dual threat quarterback and was one of Duke's more highly-touted prospects coming out of high school. He has struggled in the Blue Devils' scrimmages this year, and it appears he might not be completely adjusted to the speed of the college game just yet. It will be interesting to see his development as well as the spring progresses and whether or not he can challenge Boone for the No. 1 slot.