Roster turnover is a constant in college football — but not usually to the extent that Tennessee is experiencing this year.

“We’re not at the norm of having to replace a third of our football team,” coach Butch Jones said. “We’re having to replace half of our team.”

What’s more, Jones said, “we’re the only school in the country that has to replace both starting interior lines, offensively and defensively.”

The Vols returned starters at most other positions — quarterback, wide receiver, tight end, linebacker, defensive back — and replenished the roster by signing 32 recruits, 14 of whom enrolled early.

On the offensive line, Jones said he is encouraged by the presence of left guard Marcus Jackson, who redshirted last season after getting some playing time the previous two seasons; junior center Mack Crowder, who “has waited for this opportunity”; and freshman right tackle Coleman Thomas, one of the early enrollees.

Defensively, the return of Curt Maggitt “will help us,” Jones said. Maggitt is expected to play a big role at end/outside linebacker after missing all of last season because of a knee injury suffered in 2012. He started eight games as a freshman in 2011 and nine as a sophomore in 2012.