Paul Goldschmidt’s Troubles with Velocity

Pop quiz, hot shots: what does this video…

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… have to do with this one?

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Obviously, they’re both Paul Goldschmidt, and they’re both base hits. They’re actually the first two hits he’s collected all season long against four-seam fastballs thrown at 95 mph or above. By comparison, the Diamondbacks’ five-time All-Star slugger had 21 such hits last year, and an average of 19 from 2015 to -17.

Two hits against high velocity. Two measly, stinkin’ hits. That grim tally — a May 28 single off the Reds’ Tanner Rainey and Wednesday’s double off the Giants’ Reyes Moronta — appears to be be the primary reason why the 30-year-old first baseman has struggled so mightily this year.

I’ve checked in on Goldschmidt twice already this year, first in a dedicated look a couple weeks into the season and then more in passing shortly after A.J. Pollock went down. Almost immediately after the first piece, he went on a brief tear that raised his wRC+ to 145 (.273/.395/.505 line) by the end of April, seemingly providing an object lesson in the dangers of dwelling too long on a single bad month. But then he was utterly dreadful in May (.144/.252/.278, 48 wRC+), his worst calendar month since… well, since last September (.171/.250/.305, 35 wRC+).

New information has come to light in the wake of each piece — or new to me at least. A few days after the Pollock injury, ESPN’s Buster Olney wrote about Goldschmidt in the context of over-30 players struggling with high-velocity fastballs, though he drew the line at 96 mph and considered only batting average. More recently, both Goldschmidt and Diamondbacks manager Torey Lovullo have fielded questions about any connection between the slugger’s current slump and a bout of inflammation in his right elbow that sidelined him for five games at the beginning of September 2017, the presumed cause of the aforementioned late-season struggle.

Via Forbes’ Barry M. Bloom, Goldschmidt was dismissive of the connection. “I didn’t play that well the last month and honestly against the Dodgers [in the Division Series, where he went 1-for-11 with a homer], too,” he said. “I would like to have played better, but it had nothing to do with the elbow or the time off.” He denied the elbow was an ongoing concern, adding, “I don’t really know what last September has to do with this year.”

Lovullo was somewhat more open to the possibility of a connection, telling Bloom, “Maybe there’s something to that… I’ve asked him several times whether anything’s lingering from September of last year and he says he’s fantastic. Hitting is hard. It’s mechanical. It’s mental. And sometimes it doesn’t go the way you want to.”

Fair enough. Goldschmidt went 8-for-12 with four doubles (including the one off Montoya) in this week’s three-game series against the Giants at AT&T Park, and he’s 14-for-35 with those doubles and two homers since May 27. Through Wednesday, he had hit .233/.344/.429 with eight homers and a 112 wRC+, up from 93 since the start of the aforementioned tear but still 31 points below his career mark, and 30 below last year’s mark.

As for the fastballs, Goldschmidt’s overall performance against four-seamers this year isn’t extraordinary. Via Pitch Info splits, he’s been in the general neighborhood of both his current wRC+ (156) and his current swinging-strike rate (9.7%) against them before. Likewise for numbers against sinkers (152 wRC+, 7.1% SwStr%):

The Statcast data tells a slightly different story. Alas, its annual counts of four-seamers that Goldy has faced differs from those of Pitch Info (e.g., for 2018, 398 seen and 76 in play via Statcast, 442 seen and 83 in play via Pitch Info), but the two sources have nearly identical numbers of total fastballs (618 four-seamers, two-seamers and sinkers for the former; 616 four-and two-seamers for the latter, with sinkers included in that second count). One can surmise that the differing tallies owe to different classification algorithms, and we can work with it. Here’s what Statcast shows for Goldschmidt’s performance against all of those fastballs:

And here are his numbers for fastballs 95 mph and higher:

The lion’s share of both sets is four-seamers, 62.1% for the larger group and 77.9% for the high-velo one, and the proportions are within a few points for this year alone (64.4% and 81.5%, respectively). In both sets, Goldschmidt’s wOBA more or less converges with his xwOBA over time, and he’s gone from overperforming against expectation in 2015-16 to underperforming in 2017-18. Here’s his wOBA compared to the MLB average wOBAs (which are essentially the same as the MLB average xwOBAs) for both sets:

That’s a pretty steep drop-off. It’s even worse if you look only at Statcast’s 95-plus data for the four-seamers:

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Whoops, here’s the data:

Ouch, ouch, ouch. Here’s the 2018 wOBA laggardboard among players with at least 20 plate appearances that ended with those heaters (including walks, of which Goldschmidt has two):

Like Goldschmidt, Calhoun (3 wRC+ overall — you read that correctly), Martin (74), Inciarte (77), Sano (84), Semien (85), and Ozuna (93 wRC) are among the familiar names one finds at the wrong end of this year’s wRC+ rankings, though some of the above players are thriving nonetheless, such as Mazara (123), Taylor (120) and Bregman (117). This isn’t a one-size-fits-all explanation.

Relative to his career numbers, Goldschmidt has struggled against sliders (75 wRC+ this year, 94 career) and curves (88 this year, 116 career), but he also did so last year to an even greater degree (65 for sliders, 75 for curves) in larger sample sizes, so I don’t think that offers as satisfactory an explanation for his decline from 2017 to 2018. It’s worth noting that the Chase Field humidor could be having an effect on Goldschmidt’s performance, as well, but with the warmer months — when the ball carries further — still to come, I’ll forgo that data dive for now.

Whether Goldschmidt’s problems, particularly with high velocity, are due to the humidor, a slowed bat, his past elbow injury, a previously unreported physical issue or a mechanical issue I can’t say. But in a game increasingly dominated by hard throwers, and in a lineup that’s been one of the league’s least productive, none of this is good news for a hitter who’s perennially been one of the league’s most reliable. At least those aforementioned two hits and his recent mini-streak do offer some hope that he can withstand further exposure to the heat.