Boy, there's so many variables involved in the equation that you can't even discuss it, almost. It's not like there's nobody on base every time -- there's guys in scoring position, nobody out, crowd's going crazy. You think, "OK, I screwed up, we can't go with A. What's B, what's C, what's D?"
Who's hitting? Is he hot or cold? Where are the base runners? What's the situation? Where are we in the game? Are we on the road? Are we at home? Is it nighttime? Is it daytime? What has he done the other two at-bats? Let's say it's the seventh inning. Where he's at in the box? How'd he look taking that pitch, or how'd he look fouling that pitch off?
There's all these things going on in your head. And then you take in all this outside input and say to yourself, "Yeah -- but I don't feel good with that pitch." Because your brain tells you, "Look, you should throw this," but I haven't thrown one of those for a strike in four innings. Eventually you just have to have enough balls to say, "Screw it, I've got to do it the way I should do it, and whatever happens, happens." I can't just throw fastballs because he knows I don't have a good enough changeup today, or he knows I don't feel good with my slider today. He doesn't really know that. All he knows is that I have these five pitches I can throw. He doesn't really know that I don't feel good about this one. He may know that I don't look like I have great command because I have three walks already and I usually don't walk anybody, but he doesn't know that I don't feel good with my changeup -- so let's throw it anyway.
That's the kind of stuff you think about, and it's not planned. It's just experience. You just have to do it. But there's so many variables. We could talk for months about variables when you're trying to figure out what to throw.