The Green Bay Press-Gazette's Wes Hodkiewicz reported the announcement came during McCarthy's Wednesday news conference.
Matthews suffered a hamstring injury against the Arizona Cardinals two weeks ago and isn't yet ready. He has been plagued with hamstring issues in the past. The Packers now are down three starting linebackers -- Matthews, Nick Perry and Desmond Bishop.
Matthews was the runner-up for NFL Defensive Player of the Year honors in 2010, and he ranks No. 4 in the league this season with nine sacks. There's no question the Packers' pass rush takes a hit with Matthews sidelined.
Follow Kareem Copeland on Twitter @kareemcopeland.