Swanson originally signed with the Indianapolis Colts as an undrafted free agent on April 30. He was placed on Injured Reserve following training camp and was waived by the Colts on October 29.
GALLERY: 49ers 53-man Roster
A 22-year-old native of Waco, Tex., Swanson initially began his collegiate career at the University of Toledo before transferring to Sam Houston State University following his freshman season. He played in 41 games, registering 129 tackles, four forced fumbles, one fumble recovery, 43 passes defensed, 1.5 tackles for loss and one blocked kick. He also set a school record with 14 interceptions for the Bearkats.