Newson (Achilles tendon) and Roundtree (ankle) both were injured during Saturday's preseason opener against Jacksonville. They will revert to the Dolphins' injured reserve list once they clear waivers.
Akins sustained a knee injury in the scrimmage against the Houston Texans on Aug. 7.
Akins, Newson and Roundtree all are done for the season.
As for Jerman, his extension has him signed through the 2005 season. He originally was scheduled to become a restricted free agent after the upcoming season.
Freeman is a nine-year veteran who has spent all but one of his NFL seasons with the Green Bay Packers.
He has 477 career catches, but had only 14 receptions in 15 games with Green Bay last season.
Freeman had worked out for the Dolphins last week.