Salary cap moves usually get made before the start of the league year, in this case March 13.
Bell, a sixth-round pick out of Eastern Kentucky in 2003, was the longest-tenured member of the Dolphins and one of the most respected leaders on the team.
On the field, Bell led the Dolphins in tackles last season and he also played a position where the Dolphins don't have a lot of depth.
His departure probably means that free agent pick-up Richard Marshall will be used at safety, where he played last season for Arizona after playing cornerback for the Carolina Panthers.
The possibility does exist that the Dolphins could re-sign Bell at some point, but he's likely to see what kind of offer he can get on the open market.
Ironically, two teams who could use a safety are AFC East rival New England and the Jets.