KNOXVILLE — Opposing quarterbacks could encounter double trouble when they face Tennessee.Derek Barnett and Curt Maggitt make No. 25 Tennessee the only Football Bowl Subdivision program to return two players who had at least 10 sacks last season. After combining for 21 sacks and 35 1/2 tackles for losses season, they welcome the opportunity to see what they can do next."We've got some goals for ourselves — and as a unit, too," Barnett said.