Interesting tidbit on the roster from the LJS, 93.4% of the returning players will have used their redshirts. Frost is definitely trying to get the roster to mature, while also still be "young" eligibility-wise.
With the (relatively) new 4 game allowance to play, there's really no reason to burn a redshirt. Unless the guy is so incredibly talented as a true frosh that you can't keep him off the field. Or there is a drastic need.