Ballard says in a statement that his body never has felt the same since he sustained a severe knee injury while playing for the New York Giants in the 2012 Super Bowl.
Ballard was signed by the Giants as an undrafted rookie free agent out of Ohio State in 2010. In the Giants' 2011 Super Bowl season, he started 13 regular season games, catching 38 passes for 604 yards and four touchdowns. He was signed by New England in 2012, but missed the entire season because of the knee injury.
Ballard signed with the Cardinals in November of last year. He appeared in eight games for Arizona, three as a starter.
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