Osborne has promoted linebackers coach Byron McCall to replace Xarvia Smith as head coach.
McCall was the last head coach at Avondale in 2010 before the DeKalb County school close.
McCall also has assisted at Lithia Springs, North Cobb and South Panola in Mississippi. He was a graduate assistant coach at Mississippi State, where he played college football.
Osborne has not won more than three games in a season since 1994. The Marietta school has chosen to play a non-region schedule in 2014 after being moved up to Class AAAAAA during reclassification. Osborne finished 2-8 in each of its three seasons under Smith.