In a recent visit to Dr. James Andrews in Birmingham, Ala., for a routine check-up on his surgically repaired right knee, Shackelford learned some frustrating news. The news he feared.
He has been ruled out for the 2012-13 season. This after a tear to the anterior cruciate ligament sidelined the redshirt junior for the entire 2011 season. He'll almost certainly file for a medical redshirt, and should have two years to play two once he returns.
The question was simple, the answer the same. Frustrated?
"Yep," a sleep-deprived Shackelford said, leaning back in his chair, forcing a smile. "I'm ready to play. Obviously, it's not that time yet."
In the spring of last year, Shackelford was readying for what was to be his breakout season. An unquestioned leader for a young defense, Shackelford, who played in all 12 games with six starts in 2010, was well on his way to prominence in the Southeastern Conference.
Then disaster struck.
"He's not healthy, and that's unfortunate ‘cause he is a kid that we feel could be a leader of this football team," first-year head coach Hugh Freeze said.
A day to forget:
April 11, 2011. A day Shackelford would rather forget. Unfortunately, he can't. His career will likely be defined by it.
In a routine drill in the 11th of Ole Miss' 15 allotted spring practices, Shackelford suddenly fell to the turf of the team's indoor practice facility. Moments earlier, a reverberating pop could be heard ringing throughout the facility.
Shackelford, who had led the team the season prior with five sacks and recorded 48 tackles, began slamming his fists against the turf. Something was severely wrong, and he knew it. He couldn't get up. He removed his helmet.
The helmet joined his fists.
"If you're human and you love this game, it hits you a little bit," Shackelford said Friday. "I'm probably able to handle the situation better than other people. That's probably why I'm going through it. Other people probably couldn't go through it."
He was named the Chucky Mullins Award recipient later that month. He cried during his acceptance speech. Then, though, he could see a light at the end of the tunnel. Only a year. One year. He could push through.
"Two?" Shackelford said Friday. "Dang."
He suffered a setback earlier this year, leading to a second procedure. Even still, he'd hoped to return at some point this season. Freeze, speaking with local media in New Orleans, La., during a break from the SEC men's basketball tournament, even hinted at possibility.
"Yes, there's a chance," he said in March. "But it's certainly not something we'd feel definite about at this point."
Now, there's no chance.
"(Dr. Andrews) told me, straight up, (next) spring is when he'd advise me to come back," Shackelford said. "I wouldn't override his word. I trust his word. Just got to keep grinding. I've been working hard. He said he was impressed (with the progress) from where I came. But he just doesn't feel comfortable putting me out there in the situation that I'm in."
Shackelford leans on his faith, family and friends as he attempts to work his way back. But he's found it hard to rid himself of the disappointment. He wants to be out on the field. He wants to compete.
Most of all, he wants to feel like himself again.
"You just got to find something deep down inside you that keeps you going, keeps you hungry, keeps you still fighting," he said. "There's always someone in worse condition than you are. Whenever you try to find yourself complaining, you've got to remind yourself that it's bad, but it's also not as bad as it could be. Having a love and passion for this game, you certainly want to be out there with your teammates."
"We all know D.T. Shackelford is a born leader," strength and conditioning coach Paul Jacksons said. "He's rehabbing his knee and has continued along those lines of leading guys. He has a knack for getting them to do better, getting them to do more and getting them to give great effort."
He still has a role. Just ask linebackers coach Tom Allen. Shackelford is a leader who never stops leading, doing his best to put on a good face.
"Nobody likes what happened last year," Allen said. "They basically are sick and tired of losing. Sometimes you've just got to get to a point that you say enough's enough. I'm going to take ownership of this and we're going to get this changed.
"Even though D.T. has been out and is going to continue to be out, he plays a role in that. He's a passionate guy who doesn't like what he's seen the last two years either. I think they're hungry. They've worked really, really hard."
How to deal:
Every football player has a proverbial ticking clock. His clock sets in motion the moment he straps on his first helmet.
There's a natural progression to the clock. Pop Warner. High School. College. Pro.
A 21-year-old Shackelford is feeling his age. This was supposed to be his stock-building year, the year he shook hands with NFL scouts prior to practices in August, September and October.
His clock came to a screeching halt on The Day to Forget. When it starts up again, when his career gets back on schedule, is unclear. But he's working.
"Football, it's not just about this game. It teaches you about life. This is a life lesson," he said, taking a minute to consider what to say next. "I may have a daughter or a son one day who comes in dealing with something and they may be able to draw off my strength from what I've had to endure in my past.
"It teaches you so much about life; that's why people love this game so much. It's so close to life. That's why I love this game the way I do, and I'd be telling you a story if I said that it doesn't affect me at all that I won't be playing this year, ‘cause it hurts."
He doesn't fear his body failing him once he returns. Some players when they step on the field for the first time following such an injury are hesitant. Will the knee hold up? Shackelford has no such fears.
"I know I've got the same passion, the same fire. I believe my body will let me do it," he said. "I believe it can happen. I believe I'm going to be completely restored. I completely believe that. I feel like once I come back, it'll be well."
He has belief. It's what he holds onto, even on days like Friday, when the eternal optimist has to force a smile.