I recruited a guy whose FT rating was F.  High potential.  From day one through the entire non-conference schedule, he's been getting 12 minutes of practice time on free throws.  He's played in all 10 games, averaging a little over 8 minutes.  Work ethic is 73.  His rating is still F. 

I didn't note his high school FT%, but I'm pretty sure it wasn't 15% or something like that.  Does this make sense?

Probably just a low F.  FT% doesn't improve extraordinarily quickly...

The cutoff between a F and a D- is around 54.0%

If he started off close to 50 it could take a full season to hit a rating of 54.0.  It's fairly rare to see someone improve more than 5-6 % in a single season.  So at 12 minutes I wouldn't expect him getting past a D (57%) this season as a best case scenario.

Or depending on what his cap is and starting number was, it could improve to a D- tomorrow.

Good responses, thanks.