Davis becomes the fourth player in the class of 2011 to pledge for the Blue Devils.
Previously Downs said the Blue Devils were his leader based on teh relationship he was forming with the coaching staff and the academic opportunities.
"Coach Cutcliffe is really excited about me," said Downs. "We talked about the future of the program. I like him a lot. I really like it there. I like the location, and I like the people. I like the way the football program is run."
Downs chose Duke over interest from Virginia Tech, Virginia, Maryland, Wake Forest, and Marshall.
The 6-foot-6, 225-pound recruit recorded nine catches for 220 yards and two touchdowns in 2009.
"I would say my speed and my footwork as far as blocking are my biggest strengths," Downs said. "I would like to improve on what to do after I catch the ball. I would like to gain more yards."