Well what the eyeball test tells you in that situation is that you disagree with the metrics, rightly or wrongly, not that they're garbage. The whole point of these metrics, and so many others from the sabermetric era, is that what looks good or bad isn't always what it seems. It's not at all easy to with the eye test recognize that one catcher gets 1% more called strikes than another, and it's not immediately obvious how many runs that adds up to over thousands of pitches. But the eye test can easily spot are things like passed balls, that always look bad. But giving up a couple of passed balls more than the average catcher over the course of a season doesn't really give up very many runs. Over the years there have been many attempts, by many different people, at quantifying the value of framing, using various different approaches. And they all reach similar conclusions, that it can cost or save double-digit runs compared to the average. And they all find the same players to grade out well or not.

Now what BPros catching metrics don't tell us anything about, and don't attempt to as I don't know how it can really be quantified, is how well a catcher calls a game. But at the same time, looking at something as blunt as cERA over 127 innings is borderline useless. Statisticians stress sample sizes for a reason, it's not something to just ignore. Which teams did they catch against? Who were the pitchers? And so forth. Maybe Grandal is a horrible game caller, I honestly wouldn't know, even if I doubt it. But in terms of what can be quantified rather well, i.e blocking, throwing and framing; he is a good catcher.

The problem with using raw numbers is that the run environment changes from year to year, especially with whatevere it is they're doing with the baseball this year. Last year the league average ERA and FIP was 4.15, so far in 2019 it's 4.44. In terms of raw FIP Brewers ranked 13th in 2018, 14th in 2019. ERA- still sees a large difference, but FIP- is 97 vs 99. It does indeed depend on which stat you want to use, and in small samples xFIP which sveumrules used, especially the league- and park-adjusted xFIP-, is superior to FIP and ERA when it comes to correlation with future run prevention. Especially in this case, since the difference is HR rate, which is a notoriously noisy stat.

So essentially there's one variable, the least predictive and least reliable, that suggests the team has been significantly worse compared to last year. There's another, the second least predictive and reliable, that suggests it's been slightly worse. The remaining ones that I'm aware of (xFIP, SIERA, cFIP, DRA) all actually says that the team has been better this year. Some of them only in relative terms (i.e compared to the rest of the league), some in absolute terms.

I'm not going to claim that they necessarily have been, but there's a lot to suggest they haven't been worse. What's important to factor in is also what's going to happen going forward. The season started with Peralta and Burnes in the rotation and with Alex Wilson closing out games early on. The phase of trying to figure out what you've got and what you need was a rather rough one for the Brewers, and it's still not entirely clear who will have what role of Nelson, Anderson, Chacin, Peralta. But much is clearer now than it was early on. I believe the run prevention will be better going forward, both because the metrics suggests it, but also because I believe we will on average be using better pitchers. Whether that's through guys who have joined the club during the season (like Gio or Houser), or have gotten better as they've gotten healthier and stronger (like Jeffress), or simply using some guys differently or guys just settling in to their roles. The fact that the Brewers to this point still has had the toughest schedule is another thing to factor in, even if it's fairly minor.

And when a team outperformed their FIP last year, but are underperforming it this year, look to the defense (And luck/sequencing/randomness, but nothing to do about that so no point bothering really).