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Experimenting With Outfield Fences

The offseason is slow sometimes so here is a *fun* little thought experiment.

Tom Szczerbowski

ESPN's Hit Tracker Online classifies home runs in three different ways. You have your "Just Enough", "No Doubt", and "Plenty"--basically, "No Doubt" are deep shots, "Just Enough" are ones that barely clear the playing field, and "Plenty" covers every other homer.

This home run by something called a Caleb Gindl at Miller Park was easily classifiable as a "Just Enough" home run. This home run was special because it got me thinking about outfield fences way back in July.

This ball was hit well, but it was not hit that well. It just barely cleared the left field fence and it just barely cleared the fence in fair territory, travelling a distance of 356 feet. That's about as poorly you can hit a ball with it still managing to make it over the fence for a home run.

This home run got me thinking about how baseballs react off the bat, and specifically why it is that centre field is deeper than the corners. I contacted Alan Nathan, Physics of Baseball researcher and professor of physics at the University of Illinois, and asked him that very question. His answer:

"...What I can tell you is that balls hit to the corner fields (as opposed to CF) are not necessarily hit with lower batted ball speed. Both "theory" and "experiment" (the latter being an inspection of batted ball speeds for home runs hit in MLB) shows that the batted ball speed is actually larger for a pulled ball than for one hit to straightaway CF."

I had originally thought that the ball would travel farthest when it makes contact with the bat across the plate--that is, when the arms are fully extended and when the bat is at its maximum speed. But, I'm not a physicist, or a mathematician, or even someone who understands basic math because I studied music for four years in college. (Haha oh god why did I do four years of music.)

Anyway I was wrong! From there, another thought: what if the fences were equal distance from the plate? How would that change things? Would there be more home runs or fewer? Would it matter? Probably not, but it's the offseason, so it's not like you have anything better to do.

Changing Dimensions

Let's use the Rogers Centre to demonstrate. It is not only the home of the Blue Jays, but the outfield fences are nicely symmetrical and uniform in height (10 feet). Fences are set at distances of, from left field to right, 328 - 375 - 400 - 375 - 328. Corners are 72 feet closer to the plate than the deepest part of the park in center field. Here it is as a visual, sort of:


Now what if the outfield fences were all the same distance from the plate? Here's Alan Nathan again:

"If you arrange so that the outfield fence is always the same distance from home plate, then you either have to make the CF fence closer or the corner fences farther. The latter will reduce home runs by a lot. The former will increase home runs but not as much."

Well, what if we did both, moving the fence in and out at the same time? I wanted to use the park's dimensions as a guide and build an average from the pre-existing outfield fence distances, so using my musician math, I settled on placing all the fences at 360 feet all the way around the outfield. Here's what that looks like, with thanks to Minor Leaguer for the diagram (Is that REAL grass????).


Now let's overlay the two images, just for kicks:


Damn, that's some professional looking work right there. I tried to overlay as best I could, placing the new outfield fences at 360 feet in relation to the other image. As we can see, we'll lose some home runs in the corners, but not many. What we don't see are the home runs we would gain from fly balls that would be caught in the current, uneven field.

Changing Home Runs

This is something that will be looked at a bit father along in the article, but the question is what would the change in home runs on a yearly basis be here? That's my question anyway. Obviously you would have other things to consider, such as the decrease in doubles and triples when a ball his hit to center field, the increase in doubles and triples when a ball is hit to either corner, defensive positioning, and the like. It would certainly make for a different game.

The only way I thought of determining whether we would get more home runs or less would be to look at individual players' spray charts for the year. Since hit f/x is not exactly a thing available to the public yet, we're going to do a gross simplification and assume that all balls hit to the outfield would have had enough height to clear our new fences.

We can pull visuals of spray charts from Yahoo! Sports, and overlay them with Minor Leaguer's ballpark. Here are a handful of said charts:

J.P. Arencibia (teehee)


Home runs lost: Three? We'll say three.

Home runs gained: 12. That's a lot of fly balls!

Net gain: Nine home runs gained throughout the year at the Rogers Centre for Arencibia.

Jose Bautista


Home runs lost: Two...and a half? Two.

Home runs gained: Two!

Net gain: Zero home runs gained at home

Edwin Encarnacion


Home runs lost: Three

Home runs gained: Twelve

Net gain: Nine at home

Adam Lind


Home runs lost: One (left field)

Home runs gained: Four

Net gain: Three at home

Colby Rasmus


Home runs lost: Four!

Home runs gained: Five!

Net gain: One! Excitement!

Yes, this is a small sample of five baseball players, but since every single one had an increase, and two had a sizeable increase in home runs with equidistant 360-foot fences, I think it's fair to say that there would be a large increase in home runs with these equidistant fences.

Let's run one more little experiment to see how this might affect a real game.

Recall that Caleb Gindle's home run came way back in July? I did a bit of work waaaaay back when the idea was relatively new, so this next part may seem like an oddly specific game, but the work has already been done, so I'm sticking with it.

What we're going to do here is look at the baseball game between the Toronto Blue Jays and the Houston Astros on July 28 of this past season. It was a good game, with Colby Rasmus hitting a walk-off single to send the Jays home happy with a 48-56 record. Oh wait maybe they weren't that happy. Here's the box score from the game.

I went through all the outs and hits from this game and looked at landing spots for balls, no matter if they were caught or landed for a hit.

There were no balls hit to the corners for home runs, so in this game, no home runs would have been taken away with our new fences. There were, however, plenty of deep fly balls to center field--let's look at just how many and see how it would affect the outcome of the game.

Yes there are a ton of things that would change if we just started turning outs in to hits, like in the case of a first inning first pitch deep fly ball to center field, instead of the score being 0-0 with 1 out and no one on, as it actually would have been, the score would be 1-0 with 0 out and no one on. This would lead to the four-hitter coming up to bat and would change the entire rest of the game, but forget all that and hear me out, for science.

Changing Outs

Brandon Barnes, Top 2, 0-0, One on, One out


What happened: Flyball out. 0-0, One on, Two out.

What would happen with new fences: Home run! 2-0 Astros, None on, One out.

Edwin Encarnacion, Bot 3, 0-0, Two on, One out


What happened: Sac fly, 1-0 Jays, One on, Two out

What would happen with new fences: Home run! 3-2 Blue Jays (Don't forget, Barnes hit a two run shot in the top of the 2nd), None on, One out

Brett Wallace, Top 6, 1-1, None on, Two out


Que paso? Fly ball out to end the inning. 1-1 halfway through 6.

New fences: Tater! 4-3 Astros now because of that additional run that happened since the last image, with 2 out in the 6th with no one on.

Edwin Encarnacion, Bot 6, 1-1, None on, no outs


What happened: Double for EE, no out one on second, 1-1 game. The ball is there somewhere.

WHAT COULD HAVE BEEN: Another home run! Now a 4-4 ballgame with none out and none on in the 6th inning.

Melky Cabrera, Bot 7, 1-1, One on, One out


The real thing: Double, runners on 1st and 3rd with one out, game still 1-1

The better thing: Home run! Will this turn Melky's season around?? Game is now 6-4 in favor of the Jays. One out in the 7th inning.

J.P. Arencibia, Bot 8, 1-1, One on, One out


What happened: Brandon Barnes made a ridiculous catch. I wish I could GIF this for y'all but sadly I cannot seem to find a single highlight of this very nice catch. Oh well. J.P. flew out, runner at first held there and there were two out

What could have happened: Home run! Now 8-4 Jays. J.P.'s season gets turned around too and the Jays make the playoffs. Sigh.

Jose Reyes, Bot 8, 1-1, Two on, Two out


What: Flyout. Inning over. Still 1-1.

What about: Another home run? That sounds nice. Although, it's the same inning as the previous home run, so the runner who is now on third was actually on first for Arencibia's home run, so he has already scored. Therefore we only have one man on base, Brett Lawrie, who walked after Arencibia's home run, so it's a two run home run for Reyes. No your reasoning doesn't make any sense. 10-4 Blue Jays. I like this game better.

Emilio Bonifacio, Bot 9, 1-1, None out, None on


What: Man I'm having bad flashbacks you guys. Emilio. Why. Remember when he was the dark horse in the Marlins blockbuster. Remember how well that trade worked out? I think I'm now a pessimist, goodie. Emilio doubled here and would eventually come home as the game-winning run on Rasmus' single later in the inning BUT

BUT WHAT??? The game is already over. The Jays won 10-4, it's the bottom of the ninth. OH RIGHT.

This has been a thought experiment with outfield fences. This has been 1800 words on a thought experiment with outfield fences. Baseball is cool. I like baseball.