The 49ers are expected to sign free agent OLB Clark Haggans on Sunday. The 35-year-old Haggans was released by the Cardinals on Friday. The Niners are badly in need of depth at the position with only Parys Haralson on the depth chart behind starters Aldon Smith and Ahmad Brooks. Neither rookie drafted in April - Darius Fleming (PUP) and Cam Johnson (Practice Squad) - has panned out thus far.