To give a very rough idea that works, but pitchers can vary so much, for example some of them, when at their best, get a bunch of strikeouts, others will get a bunch of groundouts/DPs. A pitcher who doesn't throw many strikeouts but consistently makes it very hard for a ball to be hit anywhere that isn't an easy play defensively could looka lot luckier than someone who gets a lot of strike outs, but when he does get hit gets hit badly.
True, but again, it's about variation from that individual's norm. A groundball pitcher will naturally have a good BABIP relative to others. If one year it's abnormally high for that person's history, though, it doesn't necessarily reflect an improvement in skill, though often these kinds of upticks in luck result in huge contracts.
