Whether starters should play in the preseason is an argument as old as time.
Some argue the snaps are crucial to begin the year strong, while others believe the risk of injury is not worth the reward of extra snaps. Typically, younger players and those learning new schemes or fighting for a roster spot will receive more playing time in the preseason than others. Both of these things can be said of the Bears' roster as they have a lot of new faces in the building, including an entirely new coaching staff.
None of the starters played a week ago against the Dolphins, as Ben Johnson advised that the reps they got in before the game were more beneficial than the actual game.