Phillips was Oklahoma’s second player chosen in this year’s draft, following receiver Dorial Green-Beckham, and was one of two players picked in the second round.
With the Dolphins, Phillips will be paired with All-Pro Ndamukong Suh.
In four years with Oklahoma, Phillips started 17 games and finished his career with 58 tackles, nine tackles for loss and 3.5 sacks.
His final year at Oklahoma was by far his best.
Phillips started all 13 games after appearing in just four games the year before because of a back injury. In his final year with the Sooners, the 6-foot-6, 334-pound defensive tackle had seven tackles for loss and two sacks as the nose tackle in Oklahoma’s 3-4.
Phillips, who was named to the All-Big 12 Second Team by the AP, made a career-high seven tackles in his final game with Oklahoma – the Russell Athletic Bowl loss to Clemson.
Phillips declared for the NFL Draft the following day.