"This is a school that has great people, that wins and that gives me an opportunity to pursue my NFL potential," Roper, who also considered Towson and UMass, told ESPN's Joe Schad.
Oregon granted Roper his release in late May. Ducks coach Chip Kelly said then that the 6-foot-6, 204-pound Georgia native made the decision after emerging from spring drills behind starter Jeremiah Masoli.
Roper started Oregon's first three games a year ago before suffering a knee injury in overtime at Purdue, forcing him to miss the next four games.
Roper finished last year completing 48 of 91 passes for 610 yards and three touchdowns in six appearances in addition to adding 85 yards and one score on the ground.
After redshirting as a true freshman during the 2006 season, Roper will have two years to complete his final two seasons of eligibility.
Information from The Associated Press contributed to this report.