Caldwell, a native of Pageland, S.C., will be returning to his home state to coach offensive linemen for the Gamecocks. Before joining Johnson on the Vandy staff, Caldwell had served two years at North Carolina, 14 years at North Carolina State, and eight years at Furman.
"I'm confident this program can go to the next level under coach Holtz and I'm looking forward to being a part of that journey," Caldwell said in a prepared statement.
"Robbie Caldwell has earned the reputation of being an outstanding football coach," Holtz said. "Throughout his coaching career, he has displayed the remarkable ability of developing highly productive and consistent offensive lineman."
Holtz has at least one more staff position to fill after firing four assistant coaches following a disappointing 5-7 2003 season. Holtz hired East Carolina offensive coordinator Rick Stockstill as wide receivers coach last week.
Vanderbilt opens the 2004 football season vs. South Carolina on Sept. 4 in Nashville.