The Falcons signed Harrison from the practice squad to the active roster Saturday, Terrin Waack of the team's official site reports.
Harrison's addition to the active roster gives the Falcons additional depth at inside linebacker after Divine Deablo (forearm) was placed on injured reserve in a corresponding move. Harrison appeared in 10 regular-season games for the Colts in 2024, when he mostly played on special teams and logged two solo tackles and one forced fumble.