Possible to redshirt before and after season?

I know a feature added this year was that redshirting was moved to the end of the season to reflect recent rule changes around redshirting. Is it possible to also have it at the beginning?
I ask because I have some players I'd like to redshirt, but they have played in some games, against my intention. I've kept them completely off all depth charts, but they still play like 5 plays a game. I'm guessing maybe they're coming in when backups get tired? My backups depth chart is not completely filled out, so maybe I just need to do that. But was wondering if we can RS people before the season too as a way to keep them out entirely.
Open to other suggestions as well. Thanks!
I ask because I have some players I'd like to redshirt, but they have played in some games, against my intention. I've kept them completely off all depth charts, but they still play like 5 plays a game. I'm guessing maybe they're coming in when backups get tired? My backups depth chart is not completely filled out, so maybe I just need to do that. But was wondering if we can RS people before the season too as a way to keep them out entirely.
Open to other suggestions as well. Thanks!