That’s correct; not all go all the way to one, but many do, and most drop to the point where they will not grow any more next year.
The best way to do it is to leave them off the depth chart so they don’t play at all, then redshirt them at the end of the season, after the championship tournament runs, but before job changes. Then you get to use their senior year for scouting/recruiting resources both years. If you redshirt him at the start, you can’t use the resources.