Shackelford, as was proven over an impressive true freshman season in 2009, is an invaluable member of the Ole Miss defense. He can alternate between all three linebacker positions, providing depth for a rather thin unit following the departures of seniors Patrick Trahan and Lamar Brumfield.
"We've got good ones, and he's just one of them," Ole Miss head coach Houston Nutt said. "He can fly. He understands it and is just all-around solid."
More than anything, however, is the leadership the sophomore brings. He may not be the veteran presence of Cornell or even senior Allen Walker, but he's mature beyond his years.
"D.T. has a high motor and he's emotional and gets excited about playing the game," defensive coordinator Tyrone Nix said. "The other guys feed off him. He makes plays and motivates everyone around him."
Shackelford, a devout Christian, never got discouraged during his injury-riddled debut season.
He battled two separate injuries a year ago, but managed to play in 11 games with 20 tackles. He made waves early, returning his first career interception for 58 yards and a touchdown in the team's second game against Southeastern Louisiana.
"I still had a pretty good season," he said. "But overall, I think God had that in control."
When he looks back, Shackelford sees his time on the sidelines as a blessing. Though he wasn't able to contribute, he attentively observed his position and absorbed as much as he could.
"Believe it or not, I think I'm better now," Shackelford, who had three sacks in Ole Miss' second full-pad scrimmage a week ago, said.
"I'm a firm believer in Jesus Christ. I believe everything happens for a reason. I believe He allowed me to go through that time and just sit back and watch my position and watch how the older guys played. If He wanted me to play, I would have played."
Shackelford is considered a starter by the Ole Miss coaching staff. Not that Shackelford pays that praise much mind. He's the very definition of a team-first player, willing to do whatever is asked to help Ole Miss continue the momentum built from back-to-back Cotton Bowl wins.
He's not one for individual recognition.
"I still got to keep working," he said. "You never just want to stay at the same level. You want to get better every day. That's one thing I feel like I can do. But it's about the team. If the team's going good, you have to be happy. You're not always going to have your best day, so you got to get out there and get better. You're never going to be perfect."
And he's not trying to be. Each and every day, Shackelford simply follows along with his coaches' orders.
"At times, he'll get out of control and do some uncharacteristic things, but he's controlling that better, and I think he's going to make a lot of plays for us this year," Nix said.