Dallas Cowboys outside linebacker Anthony Spencer will not play Monday night against the Chicago Bears because of a strained pectoral muscle, according to ESPN Dallas.
Spencer, who was held out of practice last week, is listed as questionable on the team's injury report.
Victor Butler will start in place of Spencer.
Spencer, a former first-round pick, leads the team with nine quarterback hurries, is second with 29 tackles and has two sacks.
Strong safety Barry Church (torn Achilles tendon), Pro Bowl nose tackle Jay Ratliff (high ankle sprain) and defensive end Kenyon Coleman (hyperextended knee), each starters, are also out.