This move comes just a week or so after the Dolphins signed Brock Osweiler to a contract.
Doughty, 26, is a former seventh-round pick of the Dolphins back in 2016. He was waived coming out of the preseason and has been on and off of their practice squad the past two years.
Miami brought Doughty back on a futures contract this past January.
Doughty has yet to appear in an NFL game.
During his college career at Western Kentucky, Doughty threw for 12,855 yards while completing 68.6 of passes to go along with 111 touchdowns and 34 interceptions.