The team announced the deal Friday. In a whirlwind two months last season, the three-year veteran went from San Francisco, to playing for Seattle and back to the 49ers - then participating in all but one defensive snap in a 23-20 wild-card playoff win at Green Bay in January.
The 27-year-old Cox appeared in nine regular-season games and all three postseason contests for the 49ers, and two games for the Seahawks. He had five total tackles between the NFC West rivals.
Denver's fifth-round draft pick in 2010, Cox started nine games as a rookie with 14 passes defensed but late that season was arrested and charged with sexual assault. He was found not guilty in a Colorado court on March 2, 2012.
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