After fall camp ends and before prep begins for the first game week the head coach typically sits down with every player on the roster and discusses their role for the season. The redshirt guys get the "Hey, you competed hard during camp but there are a lot of talented and experienced guys ahead of you and it's in your best interest to develop for a year and you'll be more impactful to the team as a redshirt senior than a true freshman. Prioritize work outs and the scout team and we'll notice, etc. etc." speech. Nobody obviously likes being told they aren't good enough but some internalize it and use the year to get better and some have a bad attitude and don't.