The reason you would redshirt a player is if the timing wasn't good for them, but you envision a scenario where they contribute.

A redshirt should be earned - but I think earning a scholarship comes first. BYU isn't in the business of redshirting healthy scholarship players, they certainly wouldn't be "wasting" a redshirt on a player that isn't on scholarship.

I've heard from the coaching staff on a couple of occasions that the players in the program don't have the luxury anymore of getting a redshirt year to figure it out - too much talent and too few scholarships in the next few years.