Makes no sense to play him in this game! All it takes is one mistake to hurt him... and to have it come in a meaningless game is stupid! You get guys hurt in this game and it could effect your season early on... while most teams are mostly healthy you'd be starting behind the eight ball.
You can get hurt in regular season games too. Should he sit during those as well?
Only valid reason to sit starters is to give the backups a chance play.
You take a guy like Brady, Manning, Rodgers, Brees, and there is a very valid argument that their backup will benefit a lot more from the game reps than the starter will. Those guys know how to read a defense at game speed, their backups can't.
If your starter is still developing, it is better to give him the reps.