"The knee is fine," he said recently. "It's great."
Jeffery appeared to be one of the South's top prospects heading into his senior season. He had been second-team Class 3A all-state as a junior after registering 74 stops, 28 tackles for loss, 11 sacks, 4 forced fumbles and 5 blocked kicks in 2007.
He was so impressive as a junior that Tennessee signed him last February, knowing full well that he probably would not be healthy enough to contribute until 2010. Even Jeffery figured he was a year away from helping ... until something happened two months ago that sparked a surge of optimism.
"During the summer workouts I realized I was doing a lot more power workouts," he recalled. "I was getting a lot stronger, quicker. I felt a lot of the strength coming back."
Although the prospect of playing as a freshman helped him focus during the rehabilitation process, Jeffery had a greater motivation.
"I just wanted to get back on my feet," he said.
Defensive tackle ranks among UT's shakiest positions, with only one proven performer - senior Dan Williams - on the roster. Recognizing the opportunity for immediate playing time has spurred Jeffery all preseason.
"That's the motivation to do your best right there," he said. "It brings the best up out of you every day."
Jeffery needs very little incentive to bring the best up out of himself each day. He's one of those self-starters who loves football, whether he's playing or merely practicing.
"I bring energy to the team ... a lot of energy," he said. "I'm always positive energy ... never down."
When Tennessee's freshmen assembled at Neyland Stadium for Picture Day back in early August, Jeffery's energy and enthusiasm were unmistakable. He was wearing a big grin, in addition to his Vol uniform.
"It feels good to be back in pads," he said. "I'm getting a great feel for the program and I'm doing pretty good."
In addition to a surgically repaired knee, Jeffery faces an obstacle all freshmen must confront - getting comfortable with the complexities that differentiate college ball from high school ball.
"I'm learning all of the new stunts and things," he said. "In high school it was pretty much 'Line up here and go.' I've got responsibilities now."
Obviously, meeting those responsibilities is the key to getting on the field this season.
"Effort is the key," he said. "Just knowing what you're supposed to know and doing your job."