I'm trying to understand what makes a player's abilities (his Ball Handling, Passing, Defense Ability, etc.) improve during a season. Is it strictly game time? Does practice improve these at all?

Thanks in advance.

I really don't know, but I would guess it's a combination of practice and game play plus also a player's work ethic and his potential with maybe a touch of arbitrary variability thrown in as well. And does a severe injury throw an even greater unknown into progression/regression? I like that you just never really know how a player will progress.

What PointGuard said but also, yes, playing time is a huge factor. If I have a promising freshman who doesn't figure to get a lot of time I'll redshirt him UNLESS he's a blue chipper because red shirting those guys means they'll go pro almost positively.