Jackson signed with the Giants' practice squad Monday, Art Stapleton of The Bergen Record reports.
Jackson (knee) is questionable for the Titans' last preseason game at New Orleans, Jim Wyatt of the Titans' official site reports.
Jackson (ankle) practiced Tuesday.
The Titans placed Jackson (ankle) on injured reserve Friday, Jim Wyatt of the team's official site reports.
Jackson played 11 snaps on special teams in Sunday's 27-24 overtime win over the Chargers and brought back two punts for 11 yards.
Jackson was informed Tuesday that he's made the Titans' initial 53-man roster, Tom Pelissero of NFL Network reports.