If I have a player who's ineligible at the end of the season, I just shift all his minutes into study hall, right? 

And if that player was being redshirted anyway, is there any significant distinction between him being ineligible versus him being redshirted besides not being able to practice his skills for a few games? 

There's no need to shift minutes. He will go to summer school and come back eligible for next season. It will cost him some points in off-season development though. Also, your reputation will take a minor hit because he became ineligible.

There is no difference between ineligibles and redshirts except for the year of practice. Both will still have 4 seasons remaining except in DI where it is the player's option whether to return for his 5th yr senior season if he is a R/S.

Dean Wermer will be unhappy

I just figured I could get the most out of this kid while redshirted if I completely ignored his study hall minutes. Then he came back with a 1.2 at midterms. I boosted his SH considerably, but there was just no saving him from that. 

Luckily I plan on being at DePauw a long, long time unless I end up so successful I can jump from DePauw to a major conference team in DI, so the rep hit shouldn't hurt too much.