The biggest changes for the Auburn Tigers as they enter the 2015 season are at quarterback, running back and at defensive coordinator.

After serving as an understudy the last two seasons, Jeremy Johnson will be Auburn’s signal-caller. Roc Thomas and Peyton Barber will share backfield duties after Cameron Artis-Payne carried the ball 303 times in 2014.

And among the biggest upgrades for the Tigers is an improved defense, thanks to Michigan transfer Blake Countess and freshman Byron Cowart, the No. 1-ranked prospect in the ESPN 300, who will be important players for former Florida coach and new coordinator Will Muschamp.

Here’s a glance at our projection for the post-fall camp two-deep:

OFFENSE (HURRY-UP, NO HUDDLE)

QB1: Jeremy Johnson
QB2: Sean White

After two seasons as Nick Marshall’s backup, Johnson finally gets his chance to run Gus Malzahn’s offense. Johnson has only two starts over the last two seasons, but his career completion rate is 73 percent. According to Malzahn, his 6-foot-5, 240-pound first-string QB is also a strong running threat.

RB1: Roc Thomas
RB2: Peyton Barber

HB: Chandler Cox or Kamryn Pettway

The backfield seems in solid shape even without Artis-Payne. And even with Johnson’s strong arm, this year’s Tigers likely will still run more than they will throw. Keep an eye on third-stringer Jovon Robinson, the top junior-college running back in 2014.

X WR1: D’haquille Williams
X WR2: Melvin Ray

Z WR1: Ricardo Louis
Z WR2: Marcus Davis

Y WR1: Melvin Ray
Y WR2: Tony Stevens

T WR1: Jason Smith or Stanton Truitt

TE1: Jalen Harris or Chris Laye

Malzahn believes Williams, Ray and Louis — all seniors — are NFL prospects and poised for big seasons in 2015. Ray had just eight receptions last season but led the Tigers in yards per catch (22.8). Louis had only 261 yards in 2014, but is expected to replace Sammie Coates as Auburn’s deep threat.

LT1: Shon Coleman
LT2: Robert Leff

LG1: Alex Kozan
LG2: Devonte Danzey

C1: Austin Golson
C2: Xavier Dampeer
RG1: Braden Smith
RG2: Jordan Diamond
RT1: Avery Young
RT2: Will Adams

Kozan, who missed all of last season after suffering a weightlifting injury while at home in Colorado last summer, should be good to go. Along with teammate Young, he’s one of 81 candidates for this season’s Outland Trophy, which goes to the nation’s outstanding lineman. The winner of the Golson-Dampeer competition will be key; he will be replacing Reese Dismukes, the top center in the country last season.

DEFENSE (4-3)

BUCK1: Carl Lawson
BUCK2: Raashed Kennion

DT1: Dontavius Russell
DT2: Maurice Swain

NT1: Montravius Adams
NT2: Devaroe Lawrence

DE1: DaVonte Lambert
DT2: Byron Cowart

Adams, Lambert and touted freshman Cowart could help Auburn’s front seven rival Alabama’s in 2014. Lawson, who had 7.5 tackles for loss and four sacks as a true freshman in 2013, returns from a knee injury that sidelined him last season.

WLB1: Kris Frost
WLB2: Tre’ Williams

MLB1: Cassanova McKinzy
MLB2: Justin Garrett

SLB1: JaViere Mitchell
SLB2: Jeff Holland

Frost and McKinzy are the Tigers’ top two returning tacklers from 2014. Mitchell is another player to watch among this group, and the arrival of linebackers coach Lance Thompson from Alabama should help as well.

NB1: Josh Holsey
NB2: Tim Irvin (as safety)

BCB1: Blake Countess
BCB2: Carlton Davis

SS1: Tray Matthews
SS2: Nick Ruffin

FS1: Johnathan Ford
FS2: Stephen Roberts

FCB1: Jonathan Jones
FCB2: Javaris Davis

All-SEC selection Jones is back after making six interceptions last season, and is one of three returning starters along with Ford and Holsey. As the Tigers’ deep safety, Ford was the Tigers’ leading tackler last season, but expect that to change in 2015.

SPECIAL TEAMS

K: Daniel Carson
P: Kevin Phillips or Ian Shannon

KR: Johnathan Ford
PR: Marcus Davis