Miles is a fourth-year player from the University of Massachusetts.
Miles played in the opening game for the Bengals before being waived, re-signed and then waived again.
The 6-foot-2, 214-pounder has 49 career tackles after entering the NFL in 2010 as an undrafted free agent.
The Ravens have released rookie safety Brynden Trawick, who played in the first three games.
Trawick accidentally injured Pro Bowl kick returner Jacoby Jones in the first game against the Denver Broncos, colliding with him while he was executing a fair catch. The injury caused Jones to sprain his right medial collateral ligament and he'll be sidelined for the next four to six weeks.
The Ravens may bring Trawick back for the practice squad if he clears waivers.