Swinney made the announcement Monday at the end of Clemson's first spring practice session.
Richt joined the Tigers last season but did not play last fall. While Clemson has a vacancy at quarterback with the departure of two-year starter Cullen Harper, Richt was not expected to be in contention with front-runners Willy Korn and Kyle Parker.
Richt was expected to join a smaller school to continue his football career.
Swinney said Richt has represented the school well during his time there.