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The home run revolution has completely passed AT&T Park by

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Before you make jokes about the slap-happy Giants, note that it might not be the team’s fault.

Braves v Giants Photo by Harry How/Getty Images

Large baseball men are hitting long baseball home runs, and they’re doing it more than ever before. Home runs are up, by a bunch, and it’s all fans can talk about. Look at all these dingers? Where did all the dingers come from? Will our children be spared?

And here in San Francisco, we’re living an oblivious existence in a remote, isolated enclave, far away from the dinger scourge. The Home Run Revolution has completely passed us by.

Your first instinct is to make fun of the Giants and their players. That is fine. Run with that instinct. I’ve turned it into a career! But after spending the morning crunching numbers and actually doing “research,” I’m pretty sure that it isn’t just the Giants. It’s the park. It’s immune to whatever is going on.

And whatever is going on has something to do with how the baseballs are manufactured most likely. Two weeks ago, Ben Lindbergh and Mitchel Lichtman reported on tests run on the current baseballs being used. Their conclusion? The baseball has changed. That doesn’t have to mean that the ball is “juiced”, or that the changes were intentional Just that they’re different.

On Wednesday, Rob Arthur wrote about research that he completed on the same topic, and the results were the same. Something is different with the baseball.

Baseball’s camera- and radar-tracking technologies measure the speed of the ball shortly after the pitcher releases it and then again when it crosses the plate. By examining how much speed it loses between those two locations, we can calculate its air resistance (as measured by drag coefficient).

...

I also found a significant decrease in the drag on the ball in general over the past few seasons, with the MLB-wide average drag coefficient dropping by about 0.01 from 2015 to 2017.4 That might not sound like much, but Nathan’s calculations show that even a change that small can add up to 5 feet of distance on a well-hit fly ball,5 which in turn would be enough to make 10 to 15 percent more balls leave the yard in a given season.

The baseball is different, and it’s affecting home run rates everywhere.

Except for AT&T Park. Here’s the Giants’ home run rate on balls put in play there since the ballpark opened:

Giants home run rates at AT&T Park

Year Home runs per ball in play
Year Home runs per ball in play
2000 4.85%
2001 4.33%
2002 3.20%
2003 3.53%
2004 3.69%
2005 2.77%
2006 2.62%
2007 2.29%
2008 1.99%
2009 3.00%
2010 3.39%
2011 1.94%
2012 1.40%
2013 1.90%
2014 2.51%
2015 2.45%
2016 2.44%
2017 1.88%

They’re clearly down, and ha ha, Giants, right? But the Giants are seeing changes away from AT&T Park, just like the rest of the league.

Giants home run rates away from AT&T Park

Year Home runs per ball in play
Year Home runs per ball in play
2000 4.92%
2001 5.75%
2002 5.24%
2003 4.32%
2004 3.91%
2005 2.69%
2006 4.31%
2007 3.25%
2008 2.10%
2009 2.49%
2010 3.79%
2011 3.43%
2012 3.04%
2013 2.78%
2014 3.49%
2015 3.57%
2016 3.27%
2017 3.73%

It’s statistically insignificant compared to last year, but in a league where rates are up for everyone, it’s nice to see that the Giants are up away from AT&T Park. They’re not total freaks.

And it’s not just the Giants, either. Here is what the rest of the league is dealing with:

MLB home run rates away from AT&T Park

Year Home runs per batted ball
Year Home runs per batted ball
2000 4.09%
2001 3.98%
2002 3.70%
2003 3.76%
2004 3.95%
2005 3.66%
2006 3.91%
2007 3.62%
2008 3.63%
2009 3.77%
2010 3.45%
2011 3.44%
2012 3.83%
2013 3.59%
2014 3.22%
2015 3.81%
2016 4.44%
2017 4.90%

And here’s what the rest of the league is doing at AT&T Park:

Opponent home run rates at AT&T Park

Year Home runs per batted ball
Year Home runs per batted ball
2000 2.69%
2001 2.11%
2002 1.83%
2003 2.64%
2004 3.21%
2005 2.91%
2006 2.93%
2007 2.63%
2008 3.30%
2009 3.00%
2010 3.03%
2011 1.86%
2012 2.44%
2013 2.99%
2014 2.54%
2015 2.57%
2016 2.93%
2017 2.82%

It’s down from last year, which is an anomaly around the league. And it’s down from 2013, which is completely bizarre. While these numbers do reflect the quality of Giants pitching (see 2011, for example), they’re still outliers compared to the rest of the league.

The differences are stunning when you combine the Giants with their opponents and compare them to the rest of the league.

Home runs per batted ball, 2014-2017

Ballpark 2014 2015 2016 2017
Ballpark 2014 2015 2016 2017
LAA-Angel Stad 2.93% 3.86% 4.22% 4.79%
TEX-Rangers Bpk 2.96% 3.88% 4.79% 5.57%
ARI-Chase Field 3.35% 3.48% 4.91% 5.27%
ATL-Turner/SunTrust 3.14% 2.60% 2.96% 4.11%
BAL-Camden Yards 3.98% 5.23% 5.18% 5.27%
BOS-Fenway Pk 2.63% 3.67% 4.41% 3.40%
CHC-Wrigley Fld 3.16% 4.25% 4.05% 5.13%
CHW-US Cellular 3.50% 3.64% 4.34% 4.84%
CIN-GreatAmer BP 3.98% 4.12% 5.29% 5.91%
CLE-Progressive 3.32% 3.51% 4.67% 5.25%
COL-Coors Fld 4.34% 4.30% 4.67% 4.85%
DET-Comerica Pk 3.17% 3.38% 4.89% 4.63%
HOU-MinuteMaidPk 3.82% 4.88% 4.13% 5.52%
KCR-KauffmanStad 2.25% 2.88% 3.44% 3.36%
LAD-Dodger Stad 3.54% 4.02% 4.25% 5.20%
MIA-Marlins Pk 2.35% 2.51% 2.98% 4.09%
MIL-Miller Pk 3.90% 4.37% 4.81% 5.49%
MIN-Target Field 2.98% 3.64% 4.62% 5.36%
NYM-Citi Field 3.06% 3.88% 4.70% 4.56%
NYY-Yankee Stad3 4.29% 5.02% 5.48% 6.57%
OAK-O.co Colis 3.16% 3.07% 3.39% 5.35%
PHI-CitizensBank 3.23% 3.83% 4.80% 5.40%
PIT-PNC Pk 2.65% 2.97% 3.38% 3.33%
SDP-PetCo Pk 2.45% 4.06% 4.11% 4.52%
SEA-Safeco Fld 3.43% 4.26% 5.49% 4.83%
SFG-AT&T Pk 2.53% 2.51% 2.68% 2.36%
STL-Busch Stad 3 2.53% 2.74% 4.19% 3.70%
TBR-TropicanaFld 2.71% 4.11% 4.96% 5.20%
TOR-Rogers Ctr 4.22% 4.64% 4.73% 5.00%
WSN-Natls Park 2.48% 3.85% 4.31% 5.23%

In 2014, it was as easy to hit a homer at AT&T Park as it was in Busch Stadium. It was easier than hitting one at Petco. Since then, the other ballparks have gone up and up and up, and the Giants have stayed the same. It’s easier to hit a home run in every park in baseball compared to 2014 ... except for AT&T Park.

One final table. This one has to do with the difference between 2014 and 2017 in every ballpark (excluding the Braves and SunTrust Park).

Difference in home run rates, from 2014 to 2017

Ballpark Difference in home run rate from 2014 to 2017
Ballpark Difference in home run rate from 2014 to 2017
SFG-AT&T Pk -0.17%
COL-Coors Fld 0.51%
PIT-PNC Pk 0.68%
BOS-Fenway Pk 0.77%
TOR-Rogers Ctr 0.78%
KCR-KauffmanStad 1.11%
STL-Busch Stad 3 1.17%
BAL-Camden Yards 1.29%
CHW-US Cellular 1.34%
SEA-Safeco Fld 1.40%
DET-Comerica Pk 1.46%
NYM-Citi Field 1.50%
MIL-Miller Pk 1.59%
LAD-Dodger Stad 1.66%
HOU-MinuteMaidPk 1.70%
MIA-Marlins Pk 1.74%
LAA-Angel Stad 1.86%
ARI-Chase Field 1.92%
CIN-GreatAmer BP 1.93%
CLE-Progressive 1.93%
CHC-Wrigley Fld 1.97%
SDP-PetCo Pk 2.07%
PHI-CitizensBank 2.17%
OAK-O.co Colis 2.19%
NYY-Yankee Stad3 2.28%
MIN-Target Field 2.38%
TBR-TropicanaFld 2.49%
TEX-Rangers Bpk 2.61%
WSN-Natls Park 2.75%

And now it’s time for my conclusion: Huh.

I have no idea what this means. I showed it to a couple of smarter writers, including Lindbergh, and the responses were also “Huh.” It doesn’t have to mean anything. It could be random variance.

But it is bizarre. If the ball is different, and those differences are affecting how baseballs are slowed down by air, why is AT&T Park seemingly unaffected? According to scientists at U.C. Berkeley who agreed to be interviewed on background, it turns out there is air at AT&T Park. If the seams are smaller, which allows the baseball to travel farther because of physics, why aren’t they traveling farther in San Francisco?

This isn’t why the Giants are awful this year, but it would explain why they have just 21 home runs at home this year. It’s not just the team, because they’re right in the middle of the pack when it comes to home runs on the road. We knew it was the ballpark, mostly. I don’t think we knew the differences were this dramatic, though.

The Home Run Revolution is threatening to shatter all sorts of long-held records. And AT&T Park is completely immune for some reason. Your guess is as good as mine. Hopefully it’s much better, really, because my guess isn’t very good at all.