The hard-hitting safety from Alabama was the seventh overall selection after helping the Crimson Tide win the BCS championship last season. He's expected to become a starter for a team that allowed an NFL-high 494 points in 2011.
Barron was a two-time team captain at Alabama, where he appeared in every game over his final three seasons. The Crimson Tide led the nation in rushing, passing, scoring and total defense a year ago when Barron was a finalist for the Jim Thorpe Award, presented annually to the nation's best defensive back.
The Bucs announced the signing Friday, a day after rookies reported for training camp. The first full-squad workout is July 27.