All four were exclusive-rights free agents.
Clary moved into the starting lineup in December, taking over at right tackle in place of Shane Olivea.
Floyd saw action in six games, catching seven passes for 97 yards. Gregory played in all 16 games, seeing most of his action on special teams. McKinney became a regular on the Chargers' defensive line rotation, playing in 14 games with two starts at defensive tackle.
Cornerback Cletis Gordon is the Chargers' only exclusive-rights free agent who has yet to sign a contract.
Copyright 2008 by The Associated Press