The Raiders placed Butler (undisclosed) on the injured reserve list Tuesday.
Butler (concussion) is slated to compete for a role in the Raiders' linebacker corps this season, Hondo S. Carpenter Sr. of Sports Illustrated reports.
Butler (concussion) has been ruled out for Saturday's game against the Chiefs.
Butler will not return to Sunday's game against the 49ers after suffering a concussion.
Butler (ribs) is active for Saturday's game at Pittsburgh.
Butler (ribs) is deemed questionable to play Saturday against the Steelers.
Butler was forced out with a rib injury during Sunday's 30-24 win over the Patriots.