Random Devin Williams question: How is he so effective? This could probably also be a Mariano Rivera question. Devin has two pitches, Mariano basically one. I get that if you are looking fastball and his Bugs Bunny changeup comes, you're done. Or vice versa. But if you guess changeup and he throws it, isn't it going to be trouble? ANd vice versa? Or is the change still super difficult to hit even if you know it is coming? And for Rivera, with just the cutter, don't you get a feel for what a strike looks like? I've never played baseball at a high level so I have no idea.