Park Features In Play

Nothing is more imposing than the Green Monster (via Eric Molina).

Nothing is more imposing than the Green Monster (via Eric Molina).

A couple of months ago, I examined flyball results by focusing on how long the ball was in the air. I looked mostly at macro trends across the game, or in the case of the Mets, a drastic personnel change. But how do the ballparks themselves influence events? After all, one of the best parts of baseball is that not all ballparks are the same. Some have unique features which may allow the home team to understand all its nuances. How long is the warning track? How will balls bounce off the wall? Is the foul area large enough to get to a fly ball? Using Inside Edge data, I dove into some of these individual ballpark features and looked to see if a home team advantage exists.

Initial Background and Clerical Work

The biggest challenge with the data was how to take into account the different defensive capabilities of the outfielders. Adam Dunn may know how to read a ball off a wall perfectly, but it is still Adam Dunn having to make the play. His knowledge will not be able compensate for his “old lady driving a scooter” speed.

After trying to adjust for each player’s defense, I just gave up. Instead, I am going to provide the home team’s two-year UZR value and the home team players who played the position the most over the time frame. People can have an idea of the home team’s defensive talent, but not get lost in too many numbers.

For all the analysis, I have used the past two years worth of data. I was limited to just two seasons because Inside Edge’s detailed fielding data go back only that far. I mainly looked at how often teams were able to get extra base hits (XBH) on balls into the concerned area. In some other cases, I looked at how often teams where able to generate outs (Out%).

Green Monster, Fenway Park

Most Left Field Games Played, Fenway Park, 2012-13
Name Games Played
Daniel Nava 112
Jonny Gomes 65
Mike Carp 31
Carl Crawford 30
Scott Podsednik 28

Let’s begin with the 37-foot tall, green left field wall at Fenway Park, aptly named the Green Monster. The Green Monster is probably the most recognizable in-play feature at any ballpark. The main reason for the wall’s uniqueness is that it is a factor in almost every game. How batted balls were played off it has determined  many games over its 102-year history. Collectively, Red Sox left fielders in 2012-13, the five most-used of whom are listed above, tallied a -8 UZR.

To highlight the differences between how the visiting team and home team play the Monster, here is video of both Evan Longoria and David Ortiz hitting a ball off it:

Those were two balls with similar placement and both were fielded almost immediately by an outfielder. Ortiz is able to make it to second base while Longoria did not. Longoria is no Billy Hamilton, but he is faster than Ortiz and should have made it also.

Looking at the videos again, the key to Ortiz getting the extra base happened in the first 20 feet from home plate. Ortiz knows immediately his batted ball isn’t going to be a home run and takes off “sprinting” to first. Longoria, on the other hand, marvels at his work, hoping to see the ball clear the fearsome wall. His hit falls  short. He loses a couple of precious seconds and ends up only at first base.

In the previous two videos, both defending teams got to the ball rather quickly and got it into the infield. Clean fielding is not always the case. Handling ricochets off the wall, especially for inexperienced players or those  new to Fenway, can be tricky. Here is a video of the Diamondbacks’ A.J. Pollock completely misplaying a bounce.

Mr. Pollock is not familiar with the wall at all since he is on a National League team. He doesn’t even keep the ball contained and the right fielder ends up having to make the play.

Okay, time to see how teams did preventing extra base hits to deep left field. I grouped the teams into four groups based on how often the other teams visit Fenway. I wanted to see if teams who were more familiar with the park did better. The groups are (1) Red Sox, (2) other American League East teams, 3) American League Central and West teams and 4) National League teams. Here is how each group did preventing extra base hits:

The Incompleat Starting Pitcher
The end of the nine-inning start and how we got here.
Extra Base Hit Prevention, Fenway Park, 2012-13
Group XBH% Allowed
Red Sox 33%
Other AL East 41%
AL Central & West 44%
National League 39%

As can be seen, away teams take extra bases only 33 percent of the time while they allow extra bases at around a 40 percent clip. Over the time frame, Boston had a below-average left-field defense, so if the Red Sox defense improves, the difference could be even larger. Again, the cause for this discrepancy can be the away team gawking at just missed home runs (bringing Boston’s numbers down) or misplaying balls off the wall (increases their numbers).

One note on the Green Monster: Plays happen off of it almost every day. In every other case, the sample of data is just a fraction of the Green Monster’s.

Tal’s Hill, Minute Maid Park

Most Center Field Games Played, Minute Maid Park, 2012-13
Name Games Played
Brandon Barnes 125
Jordan Schafer 82
Justin Maxwell 71
Robbie Grossman 25
Trevor Crowe 10
Brian Bogusevic 10

I still don’t get who thought it was a good idea to build a hill in the middle of the field. Even worse, the Astros put a pole in the middle of it. Somehow I see the inspiration for this feature involving a couple 20-somethings taking a trip to Reynosa for some tequila and dried leaves filled with tetrahydrocannabinol. Then back in Houston, their bosses love it because at least every ball hit there means ESPN has a reason to put the Astros on TV. Now it is your turn to come up with something better.

While Tal’s Hill is not a dominating feature, it does cause some fielding issues for center fielders at Minute Maid Park. Here is the hill turning a routine fly ball for Brandon Barnes into a circus catch and, thankfully, not a turned ankle.

The problem with Tal’s Hill from a data accumulation standpoint is that it is rarely in play. To look at how teams fielded fly balls hit there, I used the data when the Astros were fielding and then everyone else.

Here is how the Astros and the rest of the league handled balls hit to Tal’s Hill and the area around it.

Out% for fielders and XBH% Allowed, Astros vs. Away Team
Location Out% XBH%
Away 86% 14%
Home 74% 26%

The most obvious conclusion is that if a ball falls near Tal’s Hill, every runner over the past couple of seasons  has gotten extra bases. This is not really a surprise since Tal’s Hill is more than 400 feet from home plate. The interesting bit of information is that away teams are almost twice as likely to catch a fly ball in deep center field.

Looking at the numbers a little deeper, the Astros seem willing to give up the deep ball and instead go for shallower outs. Here is the Out% and XBH% for all hits to center field.

XBH% Allowed, Tal’s Hill vs. Road
Out% XBH%
Field Depth Astros Away Team Astros Away Team % Of Balls Hit
Shallow 39% 31% 1% 2% 21%
Routine 67% 64% 3% 2% 28%
Slightly deep 96% 99% 3% 1% 29%
Deep 74% 84% 26% 16% 22%

The Astros have put a higher priority on getting to the shallow and routine fly ball, while the away team is looking to cover deep balls near Tal’s Hill.

Center Field Wall, Chase Field

Most Center Field Games Played, Chase Field, 2012-13
Name Games Played
A.J. Pollock 112
Chris Young 84
Gerardo Parra 73
Adam Eaton 48
Tony Campana 7

The balconies and wall are not the most imposing features, but do add a little difficulty in fielding. Here we see Junior Lake catching a break as the ball ricochets off the center field wall straight to Alfonso Soriano.

As with Tal’s Hill, not many balls will reach the wall at more than 400 feet from home plate.

The Diamondbacks do a good job of fielding the area; they have reached 71 percent of the batted balls for outs, while the away teams get to only 66 percent of the fly balls in that part of the park. This difference can be explained by the above-average center fielders the D-backs have employed, and that doesn’t figure to change this season.

Every ball that landed in this area or went off the wall became an extra-base hit. The main problem is the balconies are just too small for a hitter to know he will hit one (and take said extra base). Since so few balls hit them, players can’t get regular reads.

Entire Oakland Coliseum Outfield

I could have picked any large park to examine (Seattle, Colorado, Kansas City, San Diego). The key with any of these parks is that the outfielders have to try to pick their battles and know they will lose a few. There is just too much ground to cover and the defense can’t cover deep and shallow, the gaps and the line. Still, the A’s won more than their fair share, as their outfield UZR over this two-year period was +27.

Here is a case where the Indians were playing in on Sam Fuld, who hit a rope to center field for a triple. Fuld and his sub .100 ISO and six career home runs would not cause the outfield defense to play back. The outfielders are playing in and Fuld is able to take advantage of the positioning.

Or a player can be playing back and make almost the same play seem routine, as Chris Young does here:

Sometimes, you’re damned if you do and damned if you don’t. Here, Coco Crisp is playing back in anticipation of Matt Adams giving the ball a ride. Instead, Adams hits a flyball single — it was in the air for more than 4.5 seconds — that drops just in front of a diving Crisp:

Again, a team just needs to pick its poison, play the odds and stick with a plan.

So let’s look at how Oakland handles fly balls to different parts of the park. Here are Oakland, the away teams  and the difference in Out% and XBH%.

Out%, Oakland Coliseum, 2012-13
Team Field Depth LF Line LF Left Center CF Right Center RF RF Line
Oakland Deep 81.6%
Slightly Deep 56.3% 86.3% 56.1% 93.5% 66.7% 88.5% 62.8%
Routine 66.7% 98.5% 66.7% 73.8% 60.7% 91.9% 72.4%
Shallow 55.2% 64.2% 43.1% 37.4% 48.7% 54.1% 39.7%
Away Team Deep 84%
Slightly Deep 45% 76% 63% 96% 67% 90% 55%
Routine 80% 99% 70% 74% 69% 89% 69%
Shallow 53% 64% 37% 40% 46% 45% 40%
Difference Deep -3%
Slightly Deep 11% 10% -7% -3% 0% -1% 7%
Routine -13% -0% -3% -1% -8% 3% 4%
Shallow 2% -0% 6% -2% 3% 9% -1%
XBH%, Oakland Coliseum, 2012-13
Team Field Depth LF Line LF Left Center CF Right Center RF RF Line
Oakland Deep 100% 50% 18% 75% 100%
Slightly Deep 44% 12% 42% 5% 28% 12% 35%
Routine 26% 0% 26% 2% 10% 0% 12%
Shallow 24% 3% 9% 2% 5% 0% 16%
Away Team Deep 100% 85% 16% 87% 100% 0%
Slightly Deep 48% 24% 35% 2% 33% 10% 45%
Routine 18% 0% 10% 4% 16% 1% 25%
Shallow 26% 1% 17% 1% 8% 1% 33%
Difference Deep 3%
Slightly Deep -4% -12% 7% 3% -5% 1% -10%
Routine 8% 0% 16% -3% -7% -1% -14%
Shallow -2% 1% -8% 1% -2% -1% -17%

Oakland’s focus is on getting shallow outs and playing the lines. With this focus, the A’s allow more hits deep and in the center field gaps. They prevent a large number of extra-base hits right down the line compared to the away team.

Certain in-play stadium features may seem like an advantage for the home team. Home teams that understand these features best can gain an advantage when the ball is in play. Most of these features, however, other than  the Green Monster at Fenway Park, are not really large enough to matter every game. As in the case with Tal’s Hill at Minute Maid Park, the feature almost acts as a distraction for the away team. The other team positions its players to make plays with it instead of covering balls hit a shorter distance. Some parks have some unique features in play, but rarely do they affect game play.

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Jeff writes for RotoGraphs, The Hardball Times, Rotowire, Baseball America, and BaseballHQ. He has been nominated for two SABR Analytics Research Award for Contemporary Analysis and won it in 2013 in tandem with Bill Petti. He has won three FSWA Awards including on for his MASH series. In his first season in Tout Wars, he won the H2H league. Follow him on Twitter @jeffwzimmerman.
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Great article, but one minor quibble. Comparing the Longoria and Ortiz fly balls off the monster, it looks like the difference was actually that Ortiz hit the ball higher than Longoria. Ortiz beat Longoria out of the box by a tiny bit, but probably not enough for him to be ahead of Longoria as they were rounding first. I think the biggest factor for the Green Monster is that it turns routine fly outs into doubles, whereas liners off the monster would probably be doubles (or homers) anywhere.


What is the denominator in the Red Sox example? I’m trying to determine if either of these factors could be at play: The Red Sox may have had better pitchers than their competition, and/or have faster runners.

Paul G.
Paul G.

Tal’s Hill is throwback to the inclines that existed in many major league ballparks over the years, most notably Crosley Field. Flagpoles in play are also a throwback. I believe Tiger’s Stadium had one. They were trying to give Enron Field some of that old stadium feel likes lots of parks do these days. It’s not like the Astros themselves much to work with historically, having played in the Astrodome. I suppose they could have put a patch of dead grass lined with fake flowers out in that area for old time’s sake.


Flagpole was in play at Forbes Field, IIRC. If the Astros really wanted to go Forbes retro, they could haul the batting cage out there, like the Pirates did, and park it against the wall. There were ground rules for the cage.


“Oakland’s focus is on getting shallow outs and playing the lines.”

Sounds like they might also be positioning for the foul territory.