KANSAS CITY, Mo. -- Chiefs running back Jamaal Charles is going back on injured reserve after developing swelling in his surgically repaired right knee, a person familiar with the decision told The Associated Press.

The person spoke on condition of anonymity Tuesday because the Chiefs had not announced the move.

The designation means the four-time Pro Bowl running back will miss at least eight weeks, so he could return for the end of the regular season and the playoffs.

Charles only had 12 carries for 40 yards in three games this season.

The Chiefs, already thin at running back after Spencer Ware sustained a concussion Sunday, signed former Titans second-round pick Bishop Sankey on Tuesday.

They cut linebackers Sam Barrington and Sio Moore.