The 49ers placed linebacker Blake Costanzo on the injured reserve list Wednesday morning with an undisclosed injury and signed three-year veteran linebacker Kion Wilson to replace him on the 90-man roster.
Wilson spent his first three NFL seasons with three different teams. He played three games with the San Diego Chargers in 2010. The past two seasons, Wilson played five games with Carolina in 2011 and seven games, including two starts, with the Pittsburgh Steelers last year. He recorded 12 tackles for the Steelers.
Wilson played under 49ers linebackers coach Jim Leavitt at South Florida.
Costanzo, a seven-year veteran, signed with the 49ers in the offseason. After playing for the 49ers in 2011, he signed as a free agent with the Chicago Bears. Because Costanzo is a vested veteran, the 49ers did not have to designate him waived/injured in order to clear a spot on the team's 90-man roster. Costanzo will earn the split-salary figure of $423,000 while on injured reserve.