The moves were announced Tuesday night, a day after Holley was carted off the field after partially tearing his right hamstring in practice.
Westbrooks was selected by Cincinnati in the seventh round last year, but never played a game with the Bengals. He hurt his thumb and was placed on injured reserve on Aug. 27 before being released a few days later.
Westbrooks had seven interceptions in 49 games, including 41 starts, during a four-year career at Georgia Southern.
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