The 49ers announced today the signing of free agent outside linebacker Brandon Long. Outside linebacker Martail Burnett was “waived/injured” after suffering spraining a knee on Monday. Long (6-3, 254) went undrafted out of Michigan State in 2009. After agreeing to join the 49ers, Long failed a physical (foot) and spent last season out of football. Long signed a two-year deal with the 49ers on April 30 after participating in their post-draft mini-camp on a tryout basis, the 49ers waived him on June 18.