That's what I did. I figured it was pretty safe, while I was still evaluating my players. It doesn't make sense to train someone that you end up firing. I'm doing free throws this week.
My understanding is that once you start training individual skills, that you should train complementary skills, instead of sticking to one thing, so that rebounding and shot blocking and inside scoring should all be trained for the big men. That is if they are good at rebounding they can absorb shot blocking training better, etc. So you should bring all skills up. I suppose that also means that if a player is deficient at a certain skill for his position, you should try to catch that up first.