But a solid camp and positional needs helped elevate the Hewitt-Trussville product to one of only two true freshmen on the Gamecocks' opening-day two-deep depth chart.
Dunn is listed as the backup to junior center Max Holcombe. Anthony Johnson is listed behind sophomore Markis Merrill — another first-year player — at one of the wide receiver spots.
"It's very exciting, coming in my first year and with the first year of the coaching staff as well," Dunn said. "When I came in, I knew it was going to be tough, but if I put in the work and did everything, everything would fall into place. And it did."
The Gamecocks had four true freshmen among non-specialists on their opening-day two-deep a year ago. It usually takes special circumstances for a true freshman to break into the two-deep, especially on the line, and Dunn met two of them. The Gamecocks needed depth on the offensive line, and Dunn came from a big-school prep background that head coach Bill Clark believes makes him ready for the college game.
“It’s just so hard to come into this level, and that’s why when you get a guy from a bigger school who's well-coached and played in those wars with the Hoovers, the Vestavias, the Clay-Chalkvilles, it’s close to college football,” Clark said. “That’s what we saw out of Dunn — a guy who understood line calls and didn’t have to go play both sides of the ball like guys at some of the smaller schools.
"He's been able to focus on his position and he came in ready to go. Of our young guys, he was by far the most impressive and that's how he kind of earned that spot.”
Gamecocks offensive line coach Mike Bennefield called it a "wonderful pleasure" to see how fast Dunn has developed.
It helped that he was able to come in early as a priority walk-on, the silent service that gets treated in Clark's organization on the same plane as the scholarship players.
"That made me feel like I had just as good a chance as everyone else," he said.
Dunn discovered his spot on the two-deep by reading a news report. His friends texted congratulations.
"It's a big accomplishment," he said.
Johnson, meanwhile, clearly impressed in preseason practice. The Gamecocks have an abundance of receivers — young, but plentiful — but he established himself as a game-changer.
“This guy was a four-year starter in high school,” Clark said. “He’s a competitor, one of the super competitors you’ll see out there. We expected to see him do well. He probably surpassed that, and that was a guy who was playing both ways (in high school). You see him there, so he’s obviously done well.”
How much the true freshmen actually get to play Saturday at Alabama State is uncertain. Dunn said "the adrenaline is going to be unreal" if he gets called into the game.
Holcombe plans to play every snap, but if the need ever arose for him to come out, he said he has “great confidence” in Dunn.
“That he’s a true freshman on the two-deep shows a lot for his athletic ability and the confidence everybody has in him,” Holcombe said. "I've seen great things out of Casey. He's buying into the system. He's learning the system. I have full confidence in him being my back up even if he has to play at some point. I think he's going to be very good whenever he gets his opportunity and when it comes I have full confidence in him making the most of it."
He already has handled the toughest question of camp like a veteran. As the backup center, it would have been remiss not to ask who the Gamecocks' opening-day starting quarterback was going to be. Dunn didn't bite.
"I don't know who it is," he said. "I just line up and snap the ball to whoever's back there to catch it."
Al Muskewitz covers Jacksonville State sports for The Star. He can be reached at 256-235-3577.