Flu-Like Symptoms: Judge-Ment

The Yankees have been a pleasant surprise so far this year. Yes, I know, I’m the guy who has written, more than once, that April numbers shouldn’t be trusted. And they shouldn’t. But they’re also irreversible. The Bombers ended the month 15-8, tied with the Orioles for the best record in the American League. Going into play Sunday, our Playoff Odds Report gave the Yankees a 51 percent chance of making the postseason. Only Houston, Cleveland, and Boston currently sport higher odds in the American League. That’s not bad for a team PECOTA expected to finish below .500 and in fourth place.

One of the top performers has been right fielder Aaron Judge. Going into Sunday’s game, he was hitting .301/.393/.767, giving him a .347 TAv that’s second on the team to part-timer Aaron Hicks. He also led the team (and the American League) in homers with 10, several of them crushed:

And he has played a surprisingly agile right field for a man with the approximate dimensions of your typical defensive end:

But I don’t want to talk about his moonshots or his glove. I want to talk about his plate discipline. This article builds on excellent analysis of Judge by our BP Bronx team, specifically this article by Andrew Gargano and this one by Martin Nolan.

Baseball statistics are in many ways a mosaic. Individual numbers are an important part of the picture, but none of them define the picture as a whole. A batter who avoids double plays is good; if he does so by popping everything up it’s bad. A pitcher with good control is good; if he gets there by throwing middle-middle it’s bad. Most statistics need additional context.

Chasing pitches is a metric that, while not telling the whole story, at least covers some important chapters. Batters who chase pitches outside the zone tend to make weak (if any) contact on their swings. Pitchers who induce swings on pitches outside the zone are beneficiaries of said weak contact and whiffs. So batters who don’t chase—have a low O-Swing Rate, in PITCHf/x terms—usually enjoy success.

For example, here are the 10 batters (minimum 42 plate appearances through Saturday’s play, which is 60 percent of qualifying for the batting title) so far this year with the highest O-Swing Rate, i.e. they’ve chased the most pitches outside the zone:

Rank	Player	O-Swing%	BA	OBP	SLG	TAv
1	Salvador Perez	47.7%	.247	.272	.506	.259
2	Adeiny Hechavarria	47.6%	.250	.267	.318	.221
3	Ronald Torreyes	47.4%	.318	.318	.439	.257
4T	Marco Hernandez	46.9%	.286	.314	.327	.218
4T	Paulo Orlando	46.9%	.149	.184	.149	.142
6	Brandon Phillips	46.3%	.347	.380	.493	.306
7	Yangervis Solarte	45.5%	.284	.355	.400	.254
8	Corey Dickerson	44.9%	.337	.374	.651	.347
9	Pablo Sandoval	44.6%	.213	.269	.377	.221
10	Eddie Rosario	43.1%	.273	.300	.377	.224

Recall that TAv is scaled to an average of .260. So of those hitters, all but two are below average so far this year, half of them well below.

How about batters who don’t chase?

Rank	Player	O-Swing%	BA	OBP	SLG	TAv
1	Aaron Hicks	10.8%	.308	.451	.667	.351
2	Jurickson Profar	11.1%	.135	.289	.135	.196
3	Logan Forsythe	14.3%	.295	.407	.341	.302
4	Jace Peterson	14.4%	.255	.327	.362	.267
5	Eric Thames	16.1%	.350	.475	.838	.444
6	Miguel Sano	17.97%	.297	.435	.649	.348
7	Lucas Duda	18.00%	.238	.360	.571	.339
8	Brett Gardner	18.2%	.206	.325	.338	.246
9	Robbie Grossman	19.7%	.267	.413	.383	.274
10T	Aaron Judge	20.0%	.301	.393	.767	.347
10T	Seth Smith	20.0%	.238	.347	.476	.266

All but two are above average, most by a pretty good margin.

Now, telling you that batters who don’t chase tend to hit better than batters who do isn’t earth-shattering news. But here’s another feature of batters who don’t chase: They tend to be older players. Plate discipline often improves with age. Judge turned 25 the day he made that catch against Boston, and he’s older than Profar and Sano, but every other one of the low O-Swing crowd is in his age-27 season or older.

And that’s normal. We have swing data dating back to 2008. I looked at players in every season from 2008 through 2016 who had at least 300 plate appearances, which is roughly three-fifths of the way toward qualifying for the batting title. Qualitatively, 300 plate appearances implies somebody who’s at least a semi-regular. (That’s why I chose 60 percent of batting title qualification in the tables above.) And those players tend not to be young. The most extreme case was the 2009 season:

Player	O-Swing%	Age
Marco Scutaro	15.6%	33
Bobby Abreu	16.8%	35
Nick Johnson	16.91%	30
Luis Castillo	16.93%	33
Jack Cust	18.0%	30
J.D. Drew	18.7%	33
Jose Bautista	18.8%	28
Josh Willingham	18.9%	30
Chipper Jones	19.1%	37
Lyle Overbay	19.7%	32

Everybody who avoided swinging at pitches outside the strike zone that season was at least 28 years old, and the mean age was over 32. No chases for old men, apparently.

Here’s a summary of the top 10 batters for lowest chase rate by year since 2008. For each season I’ve listed the average seasonal age of the 10 players, the age of the youngest player of the 10, and the rookies among the top 10.

Ten Lowest O-Swing Rates, 2008-2016
Year	Avg Age	Youngest	Rookies
2008	29.9	24	Denard Span
2009	32.1	28
2010	29.4	23	John Jaso
2011	30.9	26
2012	28.9	25
2013	31.1	25
2014	30.0	22
2015	29.9	22	Delino DeShields
2016	30.5	25	Travis Jankowski

There are a couple interesting features of that table. First, the average seasonal age, overall, is over 30. So what Judge is doing is pretty unusual for a young player.

But check out that last column. If he keeps it up, Judge will be only the fifth rookie in 10 years to crack the top 10 in lowest chase rate. His peers are:

• 2008 Denard Span: .294/.387/.432, .294 TAv, 6 HR
• 2010 John Jaso: .263/.372/.378, .269 TAv, 5 HR
• 2015 Delino DeShields: .261/.344/.374, .259 TAv, 2 HR
• 2016 Travis Jankowski: .245/.332/.313, .238 TAv, 2 HR

Judge may not remain in the top 10 this year. And we don’t know where his rate stats will fall out. But he has already easily out-homered every rookie who’s finished in the top 10 for not chasing since data became available.

Ten years isn’t a long time, but what Judge is doing so far is unprecedented. We haven’t seen a rookie power hitter who avoids chasing pitches outside the zone as well as Judge. So far this year, his ISO is an otherworldly .466. Let’s assume he finishes the year with a more mortal .250. Since 2008, here are the rookies who’ve had an ISO of .250 or better in 300 or more plate appearances, along with their chase rates:

Player	Season	ISO	O-Swing%
Chris Davis	2008	.264	39.1%
Evan Longoria	2008	.259	28.6%
Garrett Jones	2009	.274	30.5%
Wilin Rosario	2012	.260	36.2%
Jose Abreu	2014	.264	40.9%
Randal Grichuk	2015	.272	35.7%
Miguel Sano	2015	.262	26.2%
Ryan Schimpf	2016	.315	28.9%
Trevor Story	2016	.296	30.9%

Simply stated, a power-hitting rookie who chases fewer than a quarter of the pitches thrown to him outside the zone is unprecedented in the PITCHf/x era. In fact, the only hitters since 2008 to combine a .250 ISO and a chase rate of 20 percent or less, rookie or otherwise, are Adam Dunn in 2008 and Josh Willingham in 2012.

And Judge has addressed an apparent weakness. Last season, in 95 plate appearances, his contact rate was only 58 percent, in part because he swung at 38 percent of pitches outside the strike zone, making contact with 38 percent of them. This year, he’s made contact on fewer swings outside the zone (29 percent through Saturday) but chased far less frequently.

In his entry in this year’s BP Annual, we noted: “He’s proven he can hit baseballs very far, but it’s time for the 24-year-old to prove he can make consistent contact.” To his credit, he’s missed a lot fewer pitches in the strike zone, cutting his whiff rate in the zone from 29 percent to 18 percent through Saturday. But his improved 69 percent contact rate so far this year is also a product of laying off pitches outside the strike zone.

Can he keep it up? Well, it’s only May 1. But consider this: Pitchers tend to throw fewer pitches in the strike zone to better hitters. If Judge retains the plate discipline he’s demonstrated thus far, avoiding the zone against him is going to put pitchers behind in the count, leaving them very limited options. It’s a recipe for more moonshots.