Don’t the guys he plays with directly influence his plus/minus, since that’s how you measure players?
Yes, but given Lohrei is -16 and no other Bruins defender is worse than -4, I think any of his D partners could comfortably point in his direction and say "Mason buddy, the problem is you". Not that they would of course, and of course it's not that simple and none of the others are blameless either, far from it. But it's very safe to say that right now he's the worst defender in his own end on the team. Which, as I've said up thread, is not me writing him off or thinking the Bs shouldn't persevere with him. It's just acknowledging current reality.
That said, the team's play as a whole is definitely relevant. If the Bruins could score and win more it'd be easier to cover defensive lapses, if the rest of the team played better defensively Lohrei would get exposed less, if the whole team was playing better and with more confidence it would pick Mason up with it and he'd almost certainly also be performing better. That's usually how it is with kids and depth players - they rise and fall with the stars and the team as a whole. It's probably also largely why Lohrei at least looked better in the back end of last season compared to now.
I was going to try to dig a little more into how Lohrei's being used within games, but the Natural Stat Trick website is down so we'll leave that alone. Anyway, basically they're trying to give him a lot of offensive zone draws but otherwise not sheltering him much. He's seeing solid minutes, many against quality opposition, and, like the others, doing the rounds in terms of partners. It's a heavy workload for a kid who's still learning. For all the faults I think we've seen enough to warrant sticking with him and hoping that upside fully materializes. But equally I don't think he's untouchable - if the
right deal came along that included him, I'd consider it.