When a player redshirts any year, freshman, sophomore, junior whatever year, they are listed on the roster as a redshirt Jr a redshirt Fr, a redshirt Sr. etc. Only players who do not redshirt at all are listed as So, Jr, Sr.
Carter Coughlin has played all 3 years so far so he will be called a Sr. this year not a redshirt Sr. Big Dan will not be listed as a redshirt Soph because he started more than 4 games last year. Make sense?
Fleck redshirted as many players as possible the past 2 years to give them an extra year to mature. Offensive line for sure is one place but also defensive line and anywhere else he can get by with redshirting legally a player that would not see the field more than 4 games.