The Detroit Lions have yet to play a large majority of their starters in the preseason. That is not true for almost every other NFL team in the league, as starters have been regularly getting a series, a quarter or even sometimes a half of play to get their feet wet.
Of course, the Lions are also in a bit of a unique situation. For the first two preseason games, they had a pair of joint practices with the opponent in the lead-up to the contest. Most teams only had one, if that. For coach Dan Campbell, those controlled reps during the week against an opponent have been more than enough to get their starters the experience they need.