The deal is worth $795,000 and includes a $730,000 base salary and a $65,000 signing bonus.
Moats is a 6-foot-2, 250-pound former Bills sixth-round draft pick.
Moats played collegiately at James Madison.
Moats knocked Brett Favre out of his final NFL game in 2010.
For his career, Moats has 141 tackles, five sacks and two forced fumbles.
He had a career-high 54 tackles last season.
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Aaron WIlson covers the Ravens for The Baltimore Sun