The 6-foot-5, 240-pound sophomore made the announcement Tuesday. He joins junior defensive end Eli Harold in opting to leave school.
Valles finished second in the Atlantic Coast Conference with nine sacks this season.
Valles is viewed as a raw talent, and coach Mike London wishes Valles had decided to return for another year of development.
Says London: ''He took a lot of time during the semester break to think this decision through and he feels it is the right thing to do at this time. I hate to see him go, but I want to wish him the best on his choice to declare for the NFL draft.''