Learning Something About David Dahl from One Swing

On Sunday evening, the Los Angeles Dodgers hosted the Colorado Rockies in what was legendary announcer Vin Scully’s last home game at Dodger Stadium after 67 years of calling the team. The Dodgers won, in walk-off fashion, scoring in the ninth on a Corey Seager home run that tied the score at 3-3, and again in the 10th on a home run by Charlie Culberson that clinched the National League West Division and ensured Scully’s final call in Los Angeles would come on a high note.

But Seager and Culberson only had the opportunity for their theatrics because of a home run hit in the top of the ninth inning by a Rockies player. With the Rockies down to their final strike of the ninth inning and with rookie outfielder David Dahl in a 1-2 count with two outs, this happened:

Dahl took Jansen deep on the type of pitch that immediately grabs your attention if you happen to be watching the game in real-time. The freeze-frame:


It’s a silly swing that produced a serious result. But just how silly, and can it, on its own, tell us anything about David Dahl?

First, to the matter of, “How silly?” The answer? Real silly. The more complicated answer? To follow.

The pitch was a cutter, as nearly 9 in 10 of Jansen’s have been this season, and this one in particular clocked in at 96.8 mph, nearly 3 mph faster than the average Jansen cutter. According to BaseballSavant, Jansen had thrown just 14 harder cutters all year than the one Dahl hit out. The first defining characteristic of this particular pitch was its velocity, but perhaps the most obvious was its location. More specifically, its height. This pitch was a little more than four feet off the ground, and while it wasn’t the highest cutter he’d thrown all year, he’s thrown just several dozen higher. So here we have a pretty unique Jansen cutter, one in the 94th percentile for Jansen in terms of height, and in the 98th percentile in terms of velocity. When batters, before Dahl, had swung at a Jansen cutter at least four feet off the ground this season, they’d whiffed 88% of the time — without a single hit to show. An already remarkable pitch became more remarkable, and then David Dahl went and hit it for a home run.

So, there’s the silliness of the pitch, and, by proxy, the swing. How about the silliness of the result? The filters we’ll use for the rest of this post are simply this: 95 mph or harder, and four feet off the ground and higher. No such home run had been hit prior to Dahl this year (ignore the inclusion of Dozier — that’s a data glitch). One such home run was hit last year. No such home runs were hit in 2014. Home runs like this one come about once a year. And so, to broaden the scope, instead of searching by individual year, I searched for the entire PITCHf/x era, a nearly nine-year window from 2008 to the present day. Here’s the full list of players to hit a home run on a pitch at least four feet off the ground at 95 mph or harder:

Eight homers, in nine years, by six different players. History supports that Dahl’s game-tying homer was just as silly, statistically, as it looked, visually.

But we can take this a step further. You might notice something all the non-Dahl hitters in the list above have in common. Duncan is a right-handed batter. Goldschmidt and Reynolds are both right-handed battrs. Tulowitzki and Gattis are both right-handers. Dahl is a lefty.

Here’s a plot of every home run hit by a left-handed batter against a pitch that traveled at least 95 mph in the PITCHf/x era:


You probably could have identified Dahl’s without the arrow, but I included it anyway. It’s the highest 95-or-faster pitch hit out by a lefty that we have on record. No left-handed batter before Dahl had ever cracked the four-foot threshold on a pitch 95 or harder. Lower the velocity threshold to 94, and you get just two more names. Lower it to 93, and you get just one more name. And the fun thing about all three of those extra homers? They all went over the short porch in right field at Yankee Stadium. Even by lowering the velocity 2 mph, we only get three extra data points, and they all come with asterisks. We’ve never seen a lefty in the PITCHf/x era hit a pitch quite like this one out for a home run before David Dahl took Kenley Jansen deep at Dodger Stadium on Sunday night.

And now to the matter of, “Does it tell us anything about Dahl?” Well, it’s entirely possible this is the first you’ve ever heard of Dahl, in which case, the answer is a resounding yes. Dahl is a legitimate prospect — BaseballProspectus, Baseball America and MLB all had him ranked in the top 50 of their preseason lists — but he’s not exactly a household prospect name in the way someone like Dansby Swanson or even Nomar Mazara might’ve been. And, while he’s been solid for the Rockies to the tune of a 111 wRC+ and 1.1 WAR through 213 plate appearances, he hasn’t exactly lit the world on fire like his teammate Trevor Story did earlier this season.

Even if you were aware of Dahl, though, I think this can still tell us something. As much as one swing can inform, at least. The first thing that stuck out to me was that list of players from above. Gattis, Tulo, Goldschmidt, Reynolds, Duncan. These are all incredibly strong humans with extensive power-hitting resumes. Duncan brings the group down a bit, but even he put together a seven-year big-league career based almost entirely on his power. Point is, you don’t luck into a home run like this. Martin Prado is just never going to hit a pitch like this one out. That Dahl did this at all informs us that he possesses a level of raw strength in the batter’s box that far surpasses the average big leaguer, and is perhaps a standard deviation or more above that.

And while that’s a positive angle we can take from this swing, there’s a negative angle, too, in that he swung at the pitch in the first place. Jansen got him to expand the zone with two strikes, to swing at a pitch that resulted in a whiff nearly 90% of the time prior to the dinger. Dahl made a poor tactical decision that resulted in the best possible outcome, bailed out solely by his natural talent. This quote by BP’s Christopher Crawford in his preseason writeup of Dahl seems particularly relevant:

If he doesn’t get something he can drive early, he will expand late, and is vulnerable to both soft stuff and fastballs at his throat with two strikes.

A fastball at his throat with two strikes is exactly the pitch this entire article is about, and it was mentioned as a vulnerability before the season began. Here’s an exceptionally humorous heat map, showing isolated slugging percentage by zone, that I couldn’t help but share:


Evidently, the high pitch is still a weakness for Dahl, not only in terms of production — contrary to what his swing against Jansen and the anomalous blip at the top of the heatmap might lead one to believe — but also in his discipline. Multiple evaluators doubted the legitimacy of Dahl’s sudden boost in walk rate last year in Double-A, and his 18-point strikeout- and walk-rate differential (K-BB%) doesn’t do much to quell concerns about his plate discipline.

This is probably reading too much into one, silly swing. We should probably just appreciate it for what it is: a swing that led to a home run unlike any we’ve got on record. And maybe a little more.

August used to cover the Indians for MLB and ohio.com, but now he's here and thinks writing these in the third person is weird. So you can reach me on Twitter @AugustFG_ or e-mail at august.fagerstrom@fangraphs.com.

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5 years ago

The score was 2-2, not 3-2. This was the go ahead home run