Coach Matt Nagy confirmed Wednesday that Trubisky injured his throwing shoulder on a designed quarterback keeper that gained 3 yards in the first quarter.
The play marked Trubisky's first regular-season snap since Nagy benched the former second overall pick in favor of Nick Foles in Week 3. Trubisky did not see the field again following the one rushing attempt.
Trubisky has a history of shoulder issues. He underwent offseason surgery in January to repair a partially torn labrum in his left, non-throwing shoulder. Trubisky suffered a dislocated left shoulder and partially torn labrum in Week 4 of last season against the Minnesota Vikings.
Trubisky missed one game before he returned to the starting lineup.
Trubisky, 26, finished the 2019 season 28th in total QBR (39.4), tied for 27th in touchdown passes (17), 21st in passing yards (3,138), 32nd in yards gained per pass attempt (6.1) and 28th in traditional quarterback rating (83.0).
The Bears went 8-8 and failed to reach the playoffs.
Chicago traded for Foles in the offseason and held an open quarterback competition in training camp. The Bears declared Trubisky the winner but Nagy benched the fourth-year quarterback in the second half of Chicago's Week 3 game in Atlanta. Trubisky served as Foles' backup the past five weeks.
Veteran Tyler Bray is the Bears' third quarterback and likely to take over the backup role with Trubisky injured.