Analyzing the Diamondbacks Prolonged Struggles

On June 27th, the Diamondbacks were 50-28, good for 22 games above .500 and a .641 winning percentage.

On August 15th (today), the Diamondbacks are 66-52, meaning we've gone 16-24 (0.400) in our last 40 games.

What happened? Should we expect this to continue?

First, let's break down our basic team stats in our first 78 games and compare them to our last 80 games:

I mean... the table pretty much speaks for itself. Our offense has regressed heavily (-1.05 runs scored/game), even despite the acquisition of JD Martinez, and our pitching has regressed as well, though by a lesser margin (+0.54 runs allowed/game).

However, it is interesting to note that despite this slide, our run margin was still only a moderate -5. That's equivalent to a Pythagorean Win Percentage of .487, so that suggests that we were a better team than our record (16-24) over that period indicated.

But the past is the past, let's break down the offense and the pitching to see if we can identify the gaps and what we can expect going forward.

The Offense

Let's take a more detailed look at the offense:

There are some definite changes there, though they're not all bad. The most obvious culprit is the massive drop in BAA with runners in scoring position. However, this only explains a portion of the drop in runs/game - we still had an overall drop in offense (from 98 to 85 wRC+).

The good news is that the Dbacks still managed to maintain about the same ISO while also seeing a significant increase in BB%. The Dbacks are seeing a bit of bad luck in BABIP and there are also some negative drops in HR/FB% and Hard%, though those could be partially tied to the ballparks during this stretch.

However, the 3% increase in K% is also quite a bit telling. And it's a large enough increase that it might be tied to a specific change rather than mostly being random variation (and it wasn't Yasmany Tomas coming back). Are there any key Dbacks that stand out during this stretch with abnormally high K%?

• Chris Iannetta: 40.3%
• Chris Owings: 28.9%
• JD Martinez: 28.1%
• Brandon Drury: 27.4%
• Paul Goldschmidt: 27.3%
• Daniel Delscalso: 24.8%
• Jake Lamb: 20.9%
• Ketel Marte: 17.8%
• AJ Pollock: 16.3%
• David Peralta: 15.2%

Ouch. That is ugly. But there is actually a positive from this. The only two Dbacks on this list that were below their career averages during this stetch: Jake Lamb and David Peralta. Ketel Marte was equal to his career K%. Essentially, we're seeing a collective underperformance to the majority of our offense. Generally speaking, you should always regress to the norm (which would roughly be career average), so we should expect our K% to drop quite a bit from here on through the rest of the season.

So what should we expect going forward?

Our offense overperformed in the first 78 games, but it significantly underperformed in the second half. Our expected offense should be somewhere in between 85 and 98 wRC+. Considering the spike in K% and significant drop in BABIP and BA in RISP, I would wager that we're much closer to being a 98 wRC+ than an 85 wRC+, especially with the addition of JD Martinez. If anything, I would almost expect us to be about a 98 wRC+ team going forward, just with more neutral luck on BAA RISP (~.260-.275 range).

The Pitching

The pitching shows a better picture overall. Most of our peripherals haven't changed much. We're seeing small declines in HR/9, BABIP, and LOB%, but these are very much in the realm of natural variation. Once again, we see a drop in Hard% (which, again, could be tied to the ballpark).

The reliever ERA stands out, but a lot of that is due to Randall Delgado's absence in blowout games. TJ McFarland has been beat up as our impromptu long man twice already, Rodney's one bad game during this stretch (giving up 4 runs to the Dodgers)n and Jake Barrett's implosion a couple nights ago all make our reliever ERA look worse in this fairly small sample. Chafin, Bradley, and Rodney (aside from one bad save) have been solid during this stretch and our overall bullpen peripherals aren't much worse before/after June 27th, so I'll save you from another table.

What should we expect?

It may not seem like it, but our pitching has still been performing really well during this slump. We've had some regression/variation, but overall it's still been solid. During this 40 game stretch, we still had the 7th best FIP (3rd best xFIP) in baseball. We should expect to be a roughly top 5-10 pitching staff in baseball through the rest of the season.

The Opposition

One thing to make a note of is the schedule that we played during this time. The combined record of the teams we played during this stretch is 562-498 (.530). That's a decently tough stretch. Also of note, all but two of the teams during this stretch (Red/Braves) have a FIP- of 100 or better, meaning we've faced a pretty tough pitching slate, which explains some of our offensive numbers.

Going Forward

The Arizona Diamondbacks should perform considerably better for the rest of the season. Our offense should be expected to rebound quite a bit and if our pitching holds steady like it has, we'll be be back to playing like a better-than-.500 team. Getting Robbie Ray back as Anthony Banda (currently sitting at 7 runs against HOU) has struggled (though showing some good potential) will help shore up our rotation.

The schedule does ease up a bit over the rest of the season - we have 6 games against the Padres and 9 games against the Giants, plus others - but it's not going to be an easy ride, either. Our playoffs odds still sit at 79% (538) or higher (86.7% at FG, 91.1% at BP) so we shouldn't be freaking out yet. Let's just hope we can start performing better sooner than later.