The San Francisco 49ers waived/injured linebacker Darius Fleming on Tuesday after the 2012 draft pick tore his left ACL for the second time in 14 months.

Fleming, taken in the fifth round (165th overall) by San Francisco in last year's draft, sustained the injury in a non-contact drill in Sunday's practice. The Notre Dame product spent his entire rookie season on the physically unable to perform list after tearing his ACL during minicamp in May of 2012.

If Fleming clears waivers, the 49ers will place him on injured reserve.

To fill the available roster spot, San Francisco signed rookie free agent linebacker Travis Johnson to a three-year contract.