Questionable recruits

Coach Bob Walsh writes about culture either overriding guys not buying in or forcing them to depart. The money quote: "The truth is if your culture is right it should be very hard for guys who are not bought in to survive."

A question: can it be pre-determined who will be the questionable recruits? If so, why take the chance? That is, unless the AD is dragon-flaming your neck for a better W-L record but even then who needs the probable headaches.