He previously visited the Cincinnati Bengals.
Ayers, 28, had 29 tackles, 5.5 sacks and one forced fumble last season in 15 games with three starts.
A former first-round draft pick from Tennessee, Ayers has 142 career tackles, 12 sacks and three forced fumbles.
The 6-foot-3, 274-pounder has 27 career starts in five NFL seasons.
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Aaron Wilson covers the Ravens for The Baltimore Sun