Does he have to announce the starter 90 minutes before the game or just who is active? I thought I read last week they had until 90 minutes before the game for Smith to clear the concussion tests, but we ruled him out the day before. So Harbaugh may wait until we go out on the field.
I know we wouldn't/shouldn't do this, but I think it would be cool to start with a completed Smith pass to Kaep and then go to Kaep the remainder of the game. If they did a flea flicker to someone, it would have to be Kaep throwing and therefore Kaep would be the starter, as he'd take the snap, flip it to Smith, and back to Kaep. I DO NOT recommend this, this would only be if it worked (which they can't know until it happened, so they wouldn't anyway).
Several times I got burned in fantasy football where they said injured running back X or injured wide receiver X was starting, and then that player didn't see a single snap.