Lock will undergo an MRI on Monday to determine the extent of the injury and duration of his absence.
The second-year passer went to the locker room in the first quarter after taking a sack and never returned. His right arm was in a sling after the game.
Jeff Driskel replaced Lock at quarterback, tossing a pair of touchdowns and an interception against the Pittsburgh Steelers. The Broncos dropped their second straight decision to open the season.
Denver will host the Tampa Bay Buccaneers in Week 3 before taking on the New York Jets and New England Patriots on the road.