"That just opened up another gate for me," Jeffery said following Thursday's practice. "It meant I had to learn another position, which I already knew. It's sad to see somebody go down like that but it means somebody has to step up."
Jeffery, a 6-3, 294-pound redshirt freshman from Sarasota, Fla., stepped up well enough that he started opposite Hughes in the Vols' first preseason scrimmage. That represented quite a coming-out party for a guy who had seen no meaningful action in the 24 months since suffering a traumatic ACL/MCL tear prior to his senior year of high school.
"It was a good opportunity. I got a couple of good looks," he said of the scrimmage start. "I was a little nervous. I could've done a lot better; I know that. But there's been a lot of corrections made, and I'm working on improving."
Jeffery was ranked the No. 20 tackle prospect in America by Scout.com heading into the 2008 season. Then his knee buckled and his world crumbled. He missed his entire senior season at Booker High, then spent his first fall at Tennessee trying to regain strength and flexibility in the surgically repaired knee.
"At first it was like a second guess," he recalled. "You're scared to do something because it felt a little wobbly."
The knee finally stabilized last March, enabling him to run without pain and - more importantly - without fear.
"Last spring it got a lot stronger," he said. "My squats went up, and I could just feel more strength coming off (the ball)."
Getting through spring practice and the first two weeks of preseason drills without incident has done a lot for Jeffery's peace of mind.
"The knee's holding up pretty good," he said, smiling.
New line coach Chuck Smith emphasizes using the hands to fight off blockers more than predecessor Ed Orgeron did. Jeffery is gradually learning this lesson, along with several others.
"Chuck Smith is a detailed coach," he said. "He's working on what everybody needs to work on specifically."
So, where has Jeffery made the most progress?
"I'd say striking the lineman," he said. "Getting my hands on people and staying low."
Learning to play the nose and the 3-technique keeps him busy but Jeffery welcomes the opportunity to do both.
"I'm more versatile," he said. "It helps a lot because I know what they're doing (at the 3), so it helps me know what I'm doing in my spot at the nose. And, if somebody (at either position) doesn't know what they're supposed to do, I can help 'em out."
Already thin, Tennessee's depth at defensive tackle reached a dangerous level when Marlon Walls went down. The Vols desperately need a tackle to fill the void alongside Hughes. Jeffery would like to be that guy.
"I just need to focus," he said, "and be more determined.... I'm fighting to get better, so I can help the team. I work every day to make sure I improve at something."
Whether Jeffery wins the spot opposite Hughes or not, he believes Tennessee's tackle corps will surpass its modest expectations.
"I think we're going to shock everybody," he said, flashing a confident grin.
So, what is the basis for this optimism?
"We're working out here," he said, nodding toward the practice field. "Every day."