I would wager a great deal of money Arraez doesnt keep that up against LH pitching.
Well yeah of course he's not gonna keep up a .400 OBP lol. But he's also got a 6-to-14 K/BB ratio against LHP so there isn't much reason to think he won't keep taking those great ABs and getting himself aboard. Also, while he's finally shaking out of it, Schoop has shrunk in big spots pretty much all year long while the opposite is true for Arraez. That's a big factor for me in a postseason discussion.
Like I said, it's debatable but hardly a cinch IMO.