The game was subsequently moved to Wednesday.
The Ravens last practiced on the Saturday before their Week 11 loss to the Tennessee Titans.
Monday's practice could still be rescheduled, but it wouldn't be until the afternoon at the earliest, a source told Pro Football Talk.
Sunday's positive tests mark the eighth straight day in which members of the organization contracted the virus, according to Jeff Zrebiec of The Athletic. Only one case involved a player, though it could bring Baltimore's reserve/COVID-19 designations to 23.
Pittsburgh was forced to cancel Friday's practice as it deals with its own positive tests.
The AFC North matchup, which was initially scheduled to be played Thanksgiving Day, was moved to Sunday before being pushed to Tuesday and then Wednesday.