Comparing the 2019 and 2020 Diamondbacks

The 2019 Diamondbacks had a record of 85-77, and were in the hunt for a post-season spot until almost the end of a six-month season. The 2020 Diamondbacks, with most of the same players, are on pace to lose the equivalent of 96 games, and appear to be dead in the water after five weeks, currently possessing an ongoing eight-game losing streak. What has gone wrong? To try and figure that out, I compared the 2019 and 2020 Diamondbacks using fWAR, and pro-rating last year’s figures to a 32-game season (a little less than 20%). What areas of the team have seen the steepest fall-off? And which individuals have failed to live up to their 2019 level of production?

Hitting vs. Pitching

Thus far, Diamondbacks hitters’ have been worth a total of 2.3 fWAR, while the pitchers have been worth just 0.2 fWAR. So, clearly the pitchers’ fault, right? Not necessarily. For by definition, offense on most teams will be responsible for a greater share of overall WAR than pitching - 57% is the expected figure. Also, last year, the team’s overall production was better in hitting (12th in the majors) than pitching (16th). Combining these two, in 2019, the bats were worth 23.4 fWAR, while the men on the mound were worth considerably less, only 13.9. But we can pro-rate those figures for a 32-game season, and see where we would expect the team to be at this point, based on last year’s performance.

Doing so gives us 4.6 fWAR for hitting, and 2,7 fWAR for pitching. Put another way, the hitters are 2.3 wins below their expected rate, while the pitchers are 2.5 wins off. This does point the finger of woe at our hurlers, though it seems more evenly-matched than you’d perhaps expect. There is certainly room for improvement at the plate, as well as on the mound. Looking the pitching, we can divide it further, into starters and relievers. Last year, they were responsible for 11.0 and 2.9 fWAR, which scales down to 2.2 and 0.6 fWAR for 32 games. The actual figures for our rotation and bullpen in 2020? 0.3 and -0.1. Both have failed to live up to what might have been expected, based on last season.

On the other side, it’s perhaps interesting to split the production down into the categories which make it up: offense, base-running and defense. Fortunately, Fangraps does this, with the metrics of Off, BsR and Def. In 2019, the team were actually buoyed largely by positive numbers in the last two categories, offsetting a poor showing in the first. To be specific: -32.0, 18.3 and 68.5. Those become -6.3, 3.6 and 13.5 respectively when we shrink them to the schedule so far. The comparable figures for 2020? -17.6, 1.8 and -2.1, so down in every facet of the game. Defense has been particularly significant. Last year, Arizona was ranked second-best in the majors. Now they’re very much middle of the pack, in 13th place.

Individual players

Let me start by saying it loud, for the people at the back.

Small sample size caveat applies

Ketel Marte has most plate appearances this year for the D-backs, with 134. Per Fangraphs, that’s enough for little more than strikeout and walk rates to be statistically meaningful. And of the 17 position players used by the Diamondbacks this year, only seven have even half as many PAs as Ketel. So, in a lot of cases, we are still at the point where any player can hit just about anything, due to random chance as much as their true level of talent. This is why slagging off Stephen Vogt (OPS+ last year of 110), based on his performance this season, is less justified than doing so for Jake Lamb (OPS+ last year of 76).

There are also cases where the 2020 players did not factor into the 2019 version of the team. This could be because they played elsewhere (Starling Marte, Madison Bumgarner, Junior Guerra, Hector Ronson) or were still in the minors (Daulton Varsho, Andy Young, Taylor Widener, Riley Smith). So you can’t just take a straight sum of the differences and get the totals analyzed above. But that in mind, if you went into this season expecting players to perform at their 2019 level - whatever that was - how do their actual 2020 production compare? As before, I’ve taken the 2019 fWAR, and pro-rated it to 32 games, then compared their output so far. The chart below shows the differences on a per-player level.

You can see, there are significantly more names heading towards the left of the chart - indication performance below their 2019 level - than are going in the direction of improvement. First thought: is this because the D-backs are an “older” team, so in general are on the downside of the aging curve? If that were the case, than you would tend to expect a decline on the previous season. That may be a factor, especially on the position player side. Per Baseball Reference, our average PA this year came from a player who was 29.8 years old - only the Giants are an older team in all of baseball. Arizona pitchers, though, averaged 27.9 years old, which is ninth-youngest.

However, it’s certainly not a universal explanation. S-Marte, Kole Calhoun and David Peralta are all above that average age for position players, but all have performed relatively better than would have been expected. Young players Carson Kelly and Luke Weaver have been among the biggest disappointments of 2020. In general though, the above would generally seem to line up with subjective expectations. Some people might be surprised to see Ahmed on the positive side, but that’s probably related to having watched him make strikeout on three pitches, for the last out of the game, with the tying run on third - for TWO consecutive nights!

Conversely, K-Marte has been the second-biggest shortfall. Perhaps that’s not expected, considering he’s hitting .310 this year. But his season last year was SO good, that shortfall felt almost inevitable. There’s also the matter of his power outage. Through the team’s first 32 games last year, Ketel had hit nine home-runs. To this point in 2020, he has just one. As a result, his OPS is over 150 points lower at this point (.749 vs. .901). The rest of the under-achievers seems as you’d expect: C. Kelly, Robbie Ray and Eduardo Escobar. But, of course, the biggest disappointment has been Bumgarner, whose value may actually have been helped - or, at least stopped from becoming more negative - by going on the IL.

One thing you can perhaps glean from the chart is, if the team is still to make a push for the post-season, it shows you who needs to step up their performance over the remaining 30 games. That would be, the ones toward the bottom - probably beginning with Bumgarner returning, both healthy and effective. Certainly, if their performances continue at the level they have been, it feels all but impossible for the Diamondbacks to reach the playoffs in 2020.