The NFL's Ian Rapoport later confirmed the deal is for one year.
The 6-foot, 200 pound Culliver was drafted out of South Carolina back in 2011 with the 80th overall pick in the 3rd round by the San Francisco 49ers.
After just three seasons with the 49ers, Culliver signed a contract with the Washington Redskins in 2015, but injured both his ACL and MCL during a November practice.
The Dolphins are hoping Culliver can have a similar turnaround as Brent Grimes, who also rebounded from a similar injury after joining the Dolphins.
Grimes is now on the Tampa Bay Buccaneers.
After missing 2013 with a torn ACL, Culliver had the best year of his career in 2014, totaling 15 passes defended, 4 interceptions and one forced fumble returned for a TD, along with 38 tackles.
If he can get back to his 2013 form, the Dolphins will have found a cornerback that can start opposite of Byron Maxwell.