The Miami Dolphins signed free agent quarterback Aaron Corp, adding a fourth arm to the training camp roster. To make room for Corp, who began his collegiate career at USC before transferring to Richmond, the Dolphins released long snapper Patrick Scales. Corp, who was signed in 2012 by the Buffalo Bills as an undrafted free agent and spent three days with the Dallas Cowboys this summer, is viewed as a developmental project. He'll be competing with former Delaware standout Pat Devlin, who has spent the last two years with the Dolphins, for the No. 3 spot behind Ryan Tannehill, Miami's starter, and Matt Moore, who is viewed as one of the NFL's better backups. Corp, who is 6-foot-3, 205 pounds, was a 2006 Parade All-American, but he lost the quarterback competition with Matt Barkley and decided to transfer to Richmond, where he suffered a season-ending knee injury after his first five games in 2010.