The San Francisco 49ers signed veteran linebacker Hannibal Navies and placed backup linebacker T.J. Slaughter on injured reserve Wednesday. Navies has played for Carolina, Green Bay and Cincinnati in his seven NFL seasons, starting 46 games. The Bengals waived him before training camp. He is expected to play immediately for the 49ers, who lost Slaughter to a torn tendon on his left ring finger in last Sunday's victory over Seattle. Slaughter was a key member of the 49ers' special-teams units.
