Minimum roster requirements?

Hi all,

I was thinking of taking over a team and cutting every player except my own recruiting class. Not 100% feasible, of course, so I thought I'd cut every player except my incoming class and the seniors (so when they graduate I'm left with 25 players, all freshmen).

My question is: does anyone know the minimum roster requirements? I know it depends on the playbook (in this case, I use Clemson O/4-2-5 D). But what's the smallest possible amount of players I can have? My best guess is around 40.

Any help or advice appreciated.