Vols coach Jeremy Pruitt said after practice Tuesday that Garland "was thinking of possibly transferring, we supported him all the way through, and in the end he decided to come back here."
Pruitt added that "he's a guy that I think has lots of upside."
Garland is a redshirt freshman who appeared in four games last season.
His return should boost the depth of a defensive line that has no returning starters and lost its most experienced performer when Emmit Gooden tore his right anterior cruciate ligament earlier this month.
Tennessee opens the season Aug. 31 at home against Georgia State.