Bears linebacker Roquan Smith suffered a pectoral injury on the Cowboys' opening drive Thursday night and did not return in Chicago's 31-24 win at Soldier Field.
After Dallas capped off an impressive 17-play, 75-yard touchdown drive, accounting for the first 8:57 of the game, Smith exited the field and went into the locker room.
The Bears are now down their two starting inside linebackers—Danny Trevathan has missed the last four games with an elbow injury. They're also without starting cornerback Prince Amukamara, who suffered a hamstring injury in last Thursday's win over the Lions, and defensive tackle Akiem Hicks, who hasn't played since Week 5.
Kevin Pierre-Louis took over for Smith and is playing alongside Nick Kwiatkoski, who's starting in place of Trevathan.
Smith, who was drafted eighth overall by the Bears in 2018, set a career-high with 15 total tackles last week in Chicago's win over Detroit on Thanksgiving.