The Bears announced the signing Saturday.
The Notre Dame alum and professional boxer has appeared in 64 games with 25 starts over five seasons with Indianapolis in 2012 and with Baltimore from 2008 to 2011.
The 5-foot-11, 200-pound Zbikowski recorded 89 tackles, three interceptions, eight pass break-ups and two sacks during those seasons.
He also has appeared in eight postseason contests.
The Arlington Heights, Ill., native was selected by the Ravens in the third round of the 2008 NFL Draft out of Notre Dame.