Boiman, 27, earned a Super Bowl ring last season as a member of the Indianapolis Colts, where he played in all 16 regular season games, making one start.
The 6-4, 245-pound Boiman spent the first four seasons of his NFL career with the Tennessee Titans, making a handful of starts. His best season came in 2003, when he recorded 45 tackles, 1.5 sacks and two interceptions.
The Steelers have been searching for additional depth at outside linebacker after releasing starter Joey Porter prior to the start of free agency earlier this month.
Currently, the Steelers have just three outside linebackers on their roster with NFL experience, starter Clark Haggans, James Harrison and Arnold Harrison. James Harrison is pencilled in to replace Porter in the starting lineup, while Arnold Harrison made the team as an undrafted rookie last season and saw action in seven games, making two starts, before going on injured reserve Oct. 31 with a knee injury.
One other option for the team is to move 285-pound defensive end Brett Keisel to outside linebacker.