It *can* be a predictive tool, I just don't believe it's particularly good at it most of the time. But in the case of a wild outlier case, like Kirilloff was a couple of weeks ago, it seems to be pretty good at predicting that the ship will right itself if all continues as it is. In the case of a guy like Polanco, I suspect it's extremely vulnerable to misinterpretation, as Polanco is hot garbage from one side of the plate and it's not as if he's going to normalize those PAs in time. If he's just getting unlucky from the right side of the plate, the xBA may not properly reflect that he only bats from that side of the plate ~40% of the time and that those ~60% of hot garbage PAs will never go away (and will likely only grow in time because teams will stack relievers against him intentionally).