Preseason games are games played against yourself.
The opponent is arbitrary. It is a time to clean up mental mistakes and to see who is going to make that final roster.
So no you don't play your starters very much, maybe 1 quarter.
It's for the younger guys to work on assignments, for the coaches to work on managing game clock, and calling plays smoothy and accurately. Getting the punt team on and off the field on time with the correct number of players, getting your FG team in position to go.
Preseason is extreemly important but that importance has nothing to do with who you play or even if you win.