On October 28 last year, the Diamondbacks hired Mike Butcher as their pitching coach. At the time, Chip Hale spoke about Butcher's experience working with young pitchers helped convince Arizona, he was the man for the job. "How he can help Rubby De La Rosa, Robbie Ray, Chase Anderson – all the kids that we have that need to take that next step. I think he’s done it with other pitchers that he’s had in the Angels organization and also the one year he was in Tampa. I think looking at that and then doing a lot of research on him and talking to a lot of people made me confident he’s the guy for this job... I’ve seen him work and be able to get those things out of pitchers that we need our staff to do."

Butcher had been in the same position with the Los Angeles Angels for the previous nine seasons. But he had been let go by the organization two weeks previously, as new GM Billy Eppler took over [coincidentally, on the same day as former D-backs coach, Don Baylor].There, his record has been mixed. It was noted that "Andrew Heaney and Garrett Richards had publicly complimented him for their improvement over the past two years," but on the other hand, "Butcher also oversaw the decline of Jered Weaver, as well as Richards’ inability to match his breakthrough performance in 2014."

However, our sister site at Halo's Heaven appears to have been firmly in the negative camp, stating that Butcher's dismissal "quickly gained [Eppler] hero status in the eyes of many a Halos fan." More objectively, a FanPost there compared "under and after Butcher" results for pitchers who had gone elsewhere. They found, that "of the 16 pitchers with the greatest % change in performance, 15 of them changed for the better after departing Anaheim." The author concluded, "Butcher's actual track record as the Angels pitching coach is atrocious, undoubtedly one of the worst, if not the worst, in all of MLB during his tenure." So has that carried forward to Arizona?

The case against Butcher

The overall numbers do not look good for Butcher at all. Through Independence Day, the Diamondbacks' ERA as a team had increased from 4.05 in 2015 to 4.68. Here's a more detailed comparison of the numbers this season and last.

Season K/9 BB/9 HR/9 BABIP LOB% GB% HR/FB ERA FIP xFIP 2015 7.46 3.07 1.12 .294 73.7 % 45.7 % 12.3 % 4.05 4.21 4.09 2016 7.90 3.53 1.16 .308 71.1 % 47.4 % 13.5 % 4.68 4.40 4.31

While strikeouts have increased a bit, the walk-rate this year is significantly higher, 15% up on the figure from 2015. The team is stranding fewer runners, and you won't be surprised to see that the home-run rate has gone up. Less than a handful of teams, in fact, have been allowing long-balls at a quicker pace than the Diamondbacks. When you're giving up home-runs virtually as often as the Rockies, that's never a good thing. When you break it down to the individual level, the difference becomes even more apparent. Taking a leaf from the Halo's Heaven playbook, here are the ERAs for the players who were with the D-backs both last year and this, "before and after Butcher", with a minimum of 20 innings.

Small sample size obviously applies in a few cases. All told, that's 11 of 13 pitchers who have seen their ERA increase under Butcher, compared to what they did, pitching for the same organization last year. Note: the above table does not include new arrivals, Shelby Miller, Zack Greinke and Tyler Clippard. They have all also had their ERAs increase this season, to 226,8%, 218.1% and 108.2% respectively. But even discounting them, if you presumed each pitcher had a 50-50 shot of their ERA getting better or worse, the odds of 11 of 13 getting worse is about 1.1%. The decline in performance does not appear to be random variation, folks.

The case for Butcher

On the other hand, there are ground to believe the problems should not necessarily be laid at Butcher's feat. There are a couple of significant external factors which play into the increase, and are not necessarily within the control of our pitching coach.

The declining D-backs defense

Particularly in the outfield, the Diamondbacks have simply been less effective at converting balls in play into outs this season. That's not much of a surprise. Last season, we had an outfield anchored by Gold Glover A.J. Pollock in center, with the very good Ender Inciarte and acceptable David Peralta flanking him. In 2016, we've had five different players start in CF, including our backup catcher, with most starts there going to converted middle-infielder Chris Owings. Thus far, our most regular outfielder has been Yasmany Tomas, whose glovework has been problematic, ahead of Owings and another converted infield, Brandon Drury.

This shows up in the Fangraphs defensive metrics. Thus far, defensive runs saved due to our throwing and double-plays have been the same as in 2015 - so, actually better, given the lower number of games. But the runs saved due to our fielding range has imploded completely, going from 25.1 to -7.5 so far this year. Overall, if we keep up at this pace, defense last year saved the D-backs 19.8 runs. In 2016, it will cost the Diamondbacks 9.3 runs. Because balls that drop in due to a lack of fielding range count as hits against the pitcher rather than errors, most of those additional runs are "earned", and will inflate team ERA, probably by between 0.10 and 0.20.

We can try and remove that from the equation by looking at fielding-independent pitching measures, such as FIP, which only looks at strikeouts, walks and home-runs. That paints a rather more favorable picture, both at the team and the individual levels. Team FIP has only increased from 4.21 to 4.40, and as we'll see shortly, that is not out of line for the overall increased run environment we're seeing this season. Similarly, let's break it down to the individual level and see what we find.

Name 2015 FIP 2016 FIP Change Silvino Bracho 3.70 7.41 200.3% Enrique Burgos 2.87 4.88 170.0% Patrick Corbin 3.35 5.05 150.7% Zack Godley 4.33 5.30 122.4% Josh Collmenter 4.65 5.42 116.6% Randall Delgado 3.79 4.33 114.2% Daniel Hudson 3.49 3.82 109.5% Robbie Ray 3.53 3.85 109.1% Archie Bradley 4.96 4.84 97.6% Brad Ziegler 3.44 3.19 92.7% Rubby de la Rosa 4.81 4.22 87.7% Andrew Chafin 3.35 2.86 85.4% Evan Marshall 6.13 3.94 64.3%

That's certainly a kinder picture of Butcher, with five of thirteen now improving their FIP. Given the same 50/50 odds as above, the chance of five or less improvements, occurring by random, is 29.1%. So when you take defense out of the equation, the case for blaming Butcher becomes a good deal weaker.

The offensive renaissance

You might be surprised to discover that more home-runs are being hit in the National League than in any season since 2006.Runs per game are also at their highest for a while (2009). Strikeout rate may be at an all-time high (over eight per nine innings, for the first time in National League history), but walks are up as well.

Season K/9 BB/9 HR/9 BABIP LOB% GB% HR/FB ERA FIP xFIP 2015 7.88 2.95 0.98 0.299 73.0 % 46.3 % 11.4 % 3.91 3.88 3.88 2016 8.14 3.22 1.09 0.296 72.6 % 45.6 % 12.6 % 4.15 4.13 4.16

This shows the sharp uptick in offense for the National League this year. ERA, FIP and xFIP (which is FIP with a "normal" HR/FB rate) have all increased by about one-quarter of a run. For FIP and xFIP, this league increase is actually more than the increase in the same figure for Arizona. As a result, our ranking in the NL hasn't changed. We were 11th for FIP and 10th for xFIP last year; we're 11th for FIP and 10th for xFIP this year. So it looks like the bulk of the difference in ERA could be explained by these two factors. Certainly, the 2016 D-backs' pitching is on pace for about two more fWAR than last year, despite the higher ERA.

Not so fast, Mr. Butcher

Even if that's the case, however, Butcher isn't off the hook. Because this is not supposed be a pitching staff which was expected merely to be "at or close to, a 2015 level of performance. They added the Cy Young runner-up, another All-Star starter with a 3.02 ERA last year, and a reliever with an ERA over the past three years of 2.50. That trio was worth over fourteen bWAR in 2015. Even the more cautious fWAR metric had Grienke, Miller and Clippard worth 9.5 fWAR last year. This year, that value has dropped by half or more. Through 87 games, more than half the season, they've been worth a combined 2.3 bWAR or 2.5 fWAR.

Some credit may be due -for addressing the early struggles of Grienke. He had an ERA of 5.26 through the first eight starts, but over the nine thereafter, until he went on the DL, that dropped to 2.26. There's evidence Zack has changed his approach, though there's no way to tell how much was him, and how much Butcher. But the elephant in the room is Shelby Miller-shaped. Nobody seems to have a clue what the problem is or how to fix it. In 10 starts, he had an ERA of 7.09, leading to a "disabled list" stint. [Quotes used advisedly] But in 5 starts since, his ERA has gone up to 7.23.

That's really the tipping point, for me. If Miller had been "fixed", and returned to performing at or near his 2015 level of performance, I'd probably accept the case that Mike Butcher knew what he was doing. But the obvious "wrongness", apparent even to a pitching neophyte like me, and Butcher's apparent inability to correct it, leave me much less than convinced he is the right man for the job.