Originally Posted by Blitz Dorsey
This is where BABIP can be a flawed stat IMO. A ball put in play against a soft-tossing lefty would seem to have a better chance of "finding a hole" than a ball put in play against a flamethrower. The problem with BABIP is that it pretends that the odds are the same once the ball is put into play no matter which pitcher you are facing. I would love to see the numbers over a long period of time, but I would not be surprised at all to learn that Sean Marshall's BABIP is consistently higher than that of Aroldis Chapman's. Once it becomes "consistent" it's no longer "bad luck."
Randy Johnson had a career BABIP of .291. Jamie Moyer has a career BABIP of .283.
If inducing weak contact was all about velocity, it would be a very different game.
And speaking of "consistent", Marshall has a career BABIP of .294. His BABIP in April was .400 and in May it was .444. If that was all we looked at, we might wonder if he was just getting beat around legitimately. But these outputs don't exist in a bubble. All of his other peripherals were very much in line with his career norms. Personally, I find it much, much more likely that he simply had an unsustainable stretch of "bad luck" (combination of more hard contact than usual, bad defense, balls finding holes) than that he experienced a temporary shift of true talent to the point of being unable to induce any weak contact while still striking out a ton, not walking many and keeping the ball in the yard.
As for Chapman's career BABIP, he may very well end up in the historically low range. But I wouldn't bet on it, nor rely on that as any type of argument in regards to what role he should pitch in.