The two-year veteran played the first two games of the season for New Orleans before being waived Monday. He had an interception and 25 tackles in 14 games with St. Louis in 2010.
The Lions, who were already missing safety Louis Delmas, and cornerbacks Chris Houston and Bill Bentley before Sunday's loss at San Francisco, lost cornerback Drayton Florence for at least eight weeks with a broken arm.
Detroit put Florence on the newly created IR-designated for return list. He can potentially return after being out for six weeks and practicing for two weeks.