The No. 3 overall draft pick was chosen Sunday by first-year Falcons coach Mike Smith, who indicated that Ryan will likely play just the first series of Atlanta's preseason finale Thursday night at Baltimore.
The Falcons, who went 4-12 last year, host Detroit to begin the regular season on Sept. 7.
Ryan began training camp last month second on the depth chart behind Chris Redman, but the rookie was poised enough in a preseason win Friday over Tennessee to win the job.
Ryan completed 15 of 21 passes for 102 yards, one touchdown and no interceptions. He directed a touchdown drive on his last series, the first possession of the third quarter, when Brian Finneran caught a 1-yard TD to give the Falcons a 10-3 lead.