The retention of Mike Butcher

There's obvious grounds for discontent. The Diamondbacks' ERA increased by more than a run last season, going from 4.05 to 5.09, the team's ranking dropping from ninth to dead-last in the National League. And this was a team which made a specific point of addressing pitching last winter, signing the Cy Young runner-up in Zack Greinke, and another All-Star in Shelby Miller. Both pitchers were a pale shadow of theit 2015 selves, and were joined in the column marked "underwhelming" by many others: Patrick Corbin, Randall Delgado, Daniel Hudson all struggled at one point or another, even the vaunted Robbie Ray's ERA went up in 2016.

It was a problem that seemed to get worse the longer the season went on, so it wasn't as if there was a positive trend, resulting from more Butcher . We first looked at the impact Butcher was having around the All-Star break, and it wasn't a pretty sight at that point. However, the pitching staff got palpably worse in the second half, the ERA ballooning from 4.77 to a staggering 5.50 after the break. That was the worst second-half ERA by any National League team since the Atlanta Braves' 5.57 in 2008 (yes, including all the crappy Rockies' staffs). Part of that was the departure of solid, reliable arms like Brad Ziegler and Tyler Clippard, But Greinke's ERA after the break was north of six too.

However, a good number of the mitigating factors that we discussed in July still apply. This isn't to say that Butcher was a great coach. More that the reasons for the worst-place pitching might not be entirely what we saw heading toward the mound, every other inning. Let's review these, and see how they played out over the second half of the season.

Defense

There's a perception that the Diamondbacks' defense suffered significantly last season. Let's see whether the defensive metrics bear that out.

Welp. As measured by UZR, the team's fielding overall plummeted from third in 2015, to twenty-seventh this season. This was mostly - but certainly not exclusively, a result of the outfield being much worse. That figure went from to +14.2 to -25.6, a drop-off of almost forty runs defensively; the infield, therefore, went from +9.6 to -14.3, also a drop, of about twenty-four runs. We see in particular it was a lack of range (RngR) which was the main problem, costing the 2016 D-backs about 59 runs. But all told, across the board at all positions and for all areas of glove-work, the team was about 64 runs worse than in 2015.

That doesn't entirely translate directly into ERA, but the bulk of it probably does. The D-backs surrendered 16 more unearned runs in 2016 than the previous season (69 vs. 53). If we presume those all to be part of the 64-run defensive deficit, that would still leave 48 earned runs which were actually cost by Arizona's defense this year. This works out as about 0.30 additional runs on the team ERA.This is reflected in pitching metrics which discount defense, such as FIP and xFIP: the difference between 2015 and 2016 for the Diamondbacks in these was much smaller, 0.29 for FIP and 0.25 for xFIP.

The gap between Arizona's actual ERA and its FIP, of 0.59, was the biggest in the major leagues; indeed, it was the largest gap for an NL side since the Rockies' 0.63 in 2012. FIP is generally regarded as a better predictor of future pitching performance than ERA, so there's reason to hope our hurlers weren't actually as bad as they seemed, just made to look worse by the D-backs' poor defense. Certainly, it seems fixing the latter could provide a significant dividend next year.

Increased offense

Commissioner Manfred's desire for more offense is being met. When he took over after the 2014 season, home-runs sat at 0.83 per game, the lowest rate since 1992. Just two seasons later, the rate this year was 31% up, at 1.09, the highest rate since 2006. There hasn't been anything like as much a spike in hits generally (BA is up only five points), and there are plenty of explanations for this unexpected increase (running the gamut from juiced balls to juiced players). But the bottom line is that run-scoring is up. The National League ERA, after bottoming out at 3.66 in 2014, ticked up a quarter-run the following season, and virtually by the same amount (+0.26) again last year.

As a result, the majority of teams in the NL saw their ERAs increase this season. No side lowered it by more than the Cubs' (-0.21), while the D-backs increase of 1.04 was not even the largest in the league, as the Cardinals blew theirs up by 1.14 runs (albeit from a much lower starting point, since they had a sub-three ERA in 2015). The Pirates were also there or thereabouts, at +0.99. A rising tide certainly floats all boats, and it would be unfair to blame Butcher for the unparalleled recent rate at which fly-balls exited National League parks this season.

Individual stats

But those two factors still leave us with about a half-run of team pitching decline to explain away. Time to drill down further into the data, and take a look at the pitchers in detail. The chart below shows the players who threw more than 25 innings for the Diamondbacks in both 2015 and 2016 (with the exception of Greinke and Shelby Miller, who were elsewhere in 2015, but are included for completeness). That gives us a sample size of 11 players. The chart below shows the number of innings pitched by the player each season, along with the ERA, FIP and xFIP returned. The final three columns are the percentage change in those three stats. Less than 100% = they got better in 2016; more than 100% = they got worse.

The ERA change is pretty relentless. 9 of the 11 got worse, with three players - Greinke, Godley and Miller - doubling or worse their ERAs this season. When we filter out defense and look at the change in FIP and xFIP, things aren't an awful lot better. While De La Rosa and Bradley improved in all three categories, the only other improvements are a 0.9% uptick in FIP from Ziegler, and a 14.4% in xFIP from Ray. In both metrics, 8 out of 11 declined. Even taking into account that Greinke and Miller moved into a more hitter-friendly park, there's just not any significant evidence Mike Butcher had a positive impact on the results of the Diamondbacks pitching staff this year.

But, #InHazenWeTrust. The GM likely has more information on the cause of the struggles than the raw data to which we have access. It's possible, as some have suggested, that there was an external mandate from elsewhere, e.g. Tony La Russa, etc. that hampered Mike Butcher in the execution of his duties, such as a demand to get the pitchers to throw more ground-balls. This is pure speculation, in that's I've not heard word of such a specific request, but we do recall the team telling Brandon McCarthy not to throw his cutter in 2014, so there is a precedent. For now, we'll just have to cross our fingers and hope for better in 2017, because this team isn't going anywhere otherwise.