Southerland suffered a fracture of the navicular bone in his left foot at the end of last season. He had surgery after the season but Georgia announced Friday night that tests this week revealed the stress fracture in a different location of the same bone.
The surgery was performed by Dr. Joe Johnson at St. Mary's Hospital.
Georgia director of sports medicine Ron Courson said Southerland will need about four months to recover.
Southerland has started 25 games. He led the team with 10 touchdowns in 2006.