Cardinals safety Tony Jefferson (hamstring) is listed as active Sunday against the 49ers, Mark Dalton of the Cardinals' official site reports.
Jefferson wouldn't hold such a significant role as a backup safety in the typical defense, but the Cardinals trot out 5-6 defensive backs on most snaps, meaning his heavy usage (77 percent of the defensive snaps) isn't out of left field. He's responded with 14 tackles (13 solo) and one interception for a touchdown on the season.