I have never understood most FB coach's aversion to playing multiple QBs, at least until you know you who your starter is for certain. KF is the worst. I get that QB is the most important position on the field, but that doesn't mean that you can't rotate a couple guys if they are both competent with the playbook. You do it in practice. This is especially true when you are playing one of those preseason games against a non Power-5 team. Rotate your back-up in and see if he brings a spark.
Jim Harbaugh is annoying, but a damn good coach. In his career, he has had no problem allowing QB competitions to go through camp and even into the season until he knew who his guy was. Frankly, if I was a coach I would give one series in the first half to my back-up as a matter of course just to make sure he has experience and is ready if I need him.
