Walls is a 6-foot-4, 197-pound former Denver Broncos starter who was cut by the St. Louis Rams last October after making four consecutive starts and struggling in single-coverage.
Walls, 28, who has battled shoulder and groin injuries, has had prior stints with the Kansas City Chiefs and the Oakland Raiders.
Undrafted out of Boston College, Walls is one of the tallest cornerbacks in recent NFL history.
Kansas City signed Walls to a one-year, $1.75 million contract in 2006, but he has had trouble sticking with one team over the past few seasons.
For his career, Walls has recorded 139 tackles, three forced fumbles, one interception and 28 pass deflections.
A former University of Virginia standout, Winborne recorded a career-high 21 special-teams tackles last season for Baltimore.