[kq76]

As I understand it, the answer is, "kind of, but not really". And by that I mean movement is based on multiple factors including GB% and PBABIP and those factors suppress XBH. For example, the higher a pitcher's GB%, the less flyballs they give up, which should mean less XBH (not many XBH are GBs through the infield). And the higher (better) a pitcher's PBABIP (rating, not stat), the less hits they're giving up, which includes XBH.

Also note that IRL flyball pitchers tend to have a lower (better) PBABIP (stat, not rating) so while FB pitchers' SLG against might be bad, it's more or less offset by less hits. So GB pitchers aren't necessarily better than FB pitchers like some people seem to think. And of course your defense and park matter a lot in that too. If you have a bad IF defense, but a good OF defense, and/or a large outfield, you might want more FB pitchers.

EDIT: And I should point out for the people who wish they didn't have to think PBABIP, you don't really have to. It's a pretty minor factor when it comes to a pitcher's WAR. If you really want a pitcher who suppresses Gap Power, get a GB pitcher.