The Dolphins did not disclose terms of the deal Thursday.
The 5-foot-11, 196-pound Green comes to the Dolphins from the Arizona Cardinals, where he has spent his entire, four-season NFL career. He is a likely replacement in Miami's starting lineup for Andre Goodman, who signed a five-year deal with Denver on March 1.
Green, 26, started in nine games last season for the Cardinals, appearing in a total of 13 games. He had 39 tackles and an interception in 2008.
A third-round draft choice in 2005, Green has 169 tackles, two interceptions, seven forced fumbles and six fumble recoveries in his career.