Baseball’s Anti-TTO Ballpark

I can recall a handful of baseball stats that have just blown me away upon first viewing. Most recently, I was floored by advancements in pitch-framing research, and now I can’t think about any catcher without looking up how well he does or doesn’t receive. Obviously, PITCHf/x was sort of world-changing right away, and the same goes for the glimpses we’ve had of HITf/x. Years and years ago, I thought we solved almost everything with general batted-ball data, and I also remember opening a book and seeing batting averages and slugging percentages against specific pitch types. And there was an article I read in the Hardball Times, talking about various park factors. Some of them have been obvious for a long time. But it wasn’t until that day that I realized parks can affect outcomes like strikeouts and bases on balls.

There’s every reason for that to make sense. Every single ballpark is different, so in a way, every single ballpark’s version of baseball is different. The baseball will look different to the batter, and how the batter sees the ball is sort of one of the game’s fundamental components. The batter’s decision and swing lead to everything else. But what this isn’t is intuitive, or easily explained. People don’t pay much attention to these park factors, because they’re weird and ultimately not that important. Yet they exist and ought to be acknowledged, and one park in particular is extreme in a number of ways.

PNC Park probably doesn’t get enough attention for being strange. This is presumably because it gets most of its attention for being spectacular. When people put together rankings of ballpark experiences around MLB, PNC is usually at or near the top of the list, for its beauty and sight lines and goods available for purchase. Less attention is paid to how PNC plays, as a stadium. It’s known to be somewhat pitcher-friendly, but it was never considered on the level of an old Petco or an old Safeco or AT&T. There hasn’t been a growing demand for PNC to bring in its fences.

It’s worth noting that PNC is tough on homers. By our own park factors, only the Giants and Marlins play in more dinger-suppressing home environments. Breaking it down by handedness, PNC is the seventh-toughest place on left-handed dingers, and the very toughest place on right-handed dingers. It’s a narrow edge, but in this way, PNC is the league’s most extreme something. Righties might not have a harder time going deep.

But PNC goes further than that. It’s easy to understand why a park might inflate or suppress homer totals. It isn’t so easy to understand why PNC reduces walks more than anywhere else, or why it also reduces strikeouts more than anywhere else. These are difficult concepts to grasp, but the data is the data and the absence of clear explanations doesn’t invalidate what we see in the numbers.

Over the last five years, Pirates batters rank 30th in home walk rate over road walk rate. They rank 29th in home strikeout rate over road strikeout rate. Pirates pitchers rank 27th in home walk rate over road walk rate, and they rank 26th in home strikeout rate over road strikeout rate. These are our FanGraphs park factors, and you can play around. Sort the SO and BB columns and you find the Pirates toward one end. Keep in mind, also, that those park factors have been halved.

You’re familiar with the concept of the three true outcomes. They’re the three FIP components, those being walks, strikeouts, and home runs. Let’s come up with an overall combined TTO park factor, by simply summing the factors for the three components. That’s what you’ll find in the sortable table below.

Team	HR	SO	BB	TTO
Pirates	90	95	96	281
Giants	89	99	99	287
Marlins	89	99	101	289
Twins	93	98	99	290
Cardinals	92	99	100	291
Royals	94	97	100	291
Nationals	99	97	96	292
Angels	95	100	97	292
Athletics	92	99	101	292
Red Sox	97	99	98	294
Tigers	99	96	99	294
Dodgers	99	100	97	296
Indians	97	101	98	296
Rays	96	101	99	296
Mariners	97	102	99	298
Braves	97	102	100	299
Diamondbacks	103	99	98	300
Padres	98	102	100	300
Cubs	102	100	102	304
Mets	103	102	100	305
Phillies	105	101	101	307
Rangers	107	98	102	307
Blue Jays	107	102	99	308
Astros	104	103	101	308
Orioles	110	99	100	309
Rockies	113	96	101	310
Yankees	110	100	101	311
Reds	112	102	100	314
Brewers	110	102	102	314
White Sox	112	102	107	321

Toward one extreme, there’s U.S. Cellular Field. A known bandbox, it inflates homers, strikeouts, and walks. At the other end is PNC, reducing all three pretty heavily. It’s not simply in order of pitcher-friendliness, because pitchers want more strikeouts, and this table also isn’t weighted, but it is sort of in order of balls in play. In three different ways, PNC encourages hitters to hit the ball and hit the ball fair, in front of the fences. The park is a full two standard deviations from the TTO mean.

The end result of everything is simple. Put it all together and PNC is pitcher-friendly, a little bit. The game is built on runs, and in Pittsburgh, there will be fewer runs. That’s not unlike saying that Matt Garza, Ervin Santana, and Ubaldo Jimenez are all probably roughly three-win pitchers. That’s true, and it gets to the heart of the matter, but what’s really interesting are the details and the processes. The things that make the free-agent starters different. The reasons why PNC is what it is. We know that the average plate appearance isn’t changed very much by whatever it is that’s causing PNC to reduce walks and whiffs. But we also know, beyond most reasonable doubts, that PNC does reduce walks and whiffs, along with home runs, and that’s fascinating. Why does PNC lead to a greater rate of balls put in play? How does this affect the rest of the game? Is there a way for the Pirates to leverage this? What does this mean for player evaluation? In what way is PNC’s pitcher-batter interaction unique?

I’m not sure the average person appreciates that every single ballpark is incredibly complicated, and little things you wouldn’t think would make a difference can make a difference in the actual gameplay. There are obvious ballpark traits and less obvious ballpark traits, with less obvious consequences, but there are so many consequences and the ones in PNC make it particularly unusual. There’s something going on there — somethings — and there’s science to be done. As long as there’s science, baseball will never grow stale.