Including an exhibition set against the Cubs, there’s only been a handful of games played at the new Yankee Stadium, to date. Yet, it seems like baseballs are flying out of the new ballpark in the Bronx. Wondering about this, on April 18th, as the Cleveland Indians were pounding the Yankees in the House that Stein Built, I dashed off the following question to Greg Rybarczyk who runs the website Hit Tracker and who knows a thing or two about homeruns, park factors, and such:
The homeruns have been flying out of the new Yankee Stadium, especially to right field, albeit over just a few games. I was wondering if you’ve done any analysis on this, or had some thoughts on it, that you would be willing to share?
Much to my pleasure, Greg Rybarczyk responded with the following:
I have been watching the balls fly in the Bronx, and while what the Indians are doing today is far beyond anything I expected, I did expect more home runs in right field at the new park, due to the shorter fence in that direction. However, there is another factor that I am tracking that I think is at play as well: the ball in use this year in MLB seems to be slightly livelier than the ball used last year or in other recent years.
As for the fence differences, I can best explain that by showing a diagram.
[Click on the thumbnail below to enlarge it.]
I created this by using actual prints from the new stadium, and by using high resolution satellite photos for the old stadium. You may have heard that the dimensions at the new park are the same as the old park, but that is not strictly true. In certain spots the distances are the same or similar, but there are significant differences in the fence line. As you can see in the diagram, most of right field is shorter in the new park, by as much as 9 feet, but more typically by 4-5 feet (the blue dotted lines in the corners are scale markings that are 4 feet apart.) In center field, the new park is actually a bit deeper, and in left field, the parks are very similar. From some analysis I’ve done on home runs, these differences would tend to increase home runs overall, and particularly in middle-to-lower power hitters.
The fence distances are not the only difference: in a few places, the fence is shorter (particularly the right field corner). A typical conversion factor for fence height to distance is that lowering a fence by 1 foot is roughly equal to moving it 0.84 feet closer to home plate. So, with the right field fence being a couple feet shorter in the new park, this is like moving it in a foot and a half or so. Minor, but I thought I’d mention it.
The possible lively ball is something I’ve been tracking by looking at average weather-neutralized home run distances. Let me explain that before I go on. I have tracked all home runs for the past three seasons, and for each, I have noted the altitude and weather that each was hit in. After figuring out how far a given home run actually flew (I call this “true distance”), my Hit Tracker program allows me to adjust the altitude and weather to a standard set of conditions and see how far the ball would have gone. I call that “standard distance”. The idea is that a home run hit in Coors Field, or a home run hit on a 100 degree day in Arlington, Texas, or a home run hit into a strong wind at Wrigley Field, can all be compared by taking out those atmospheric influences and comparing their standard distances.
So, very early this season (actually on the second full day of games), I had already noticed that balls were seemingly flying farther than they usually do, so I checked my numbers, and noticed that the standard distances of all the home runs around MLB were a lot longer than those hit in 2008. Since then, I’ve continues tracking this, and what was little more than a feeling and some numbers off a very small sample size have become a lot more compelling: the first 350 home runs this year are flying, on average, about 6 feet farther than last year. The likellihood that such a difference could come about by chance is exceedingly low, less than 0.0031% the last time I ran the stats on that. I’ve tried to come up with some other possible ways that league-wide homers could be flying so much farther, given that the weather is already factored out, and the ball is the most likely explanation.
Now, if these numbers wre happening in isolation, I’d be more cautious about theorizing on this, but we are at 2.26 home runs per game (a high rate considering it’s April, the coldest month of the year on average), and on the observation side, my own eyes (which have watched every one of the more than 15,000 home runs hit in the last 3 + seasons) tell me the ball is carrying farther, and lots of announcers (who also see a lot of fly balls hit) are saying the same thing. (You might also want to check out this thread from the “Book Blog” regarding the possible lively ball.)
So, according to Greg Rybarczyk’s research, it should be easier to hit homeruns in this Yankee Stadium – compared to the last one – as a result of the way the outfield fences have been set up in the new park and perhaps also because of the balls being used (everywhere in baseball today). Reading this, I asked Greg this follow-up question:
How many games should we be looking at, in terms of games played at the new Yankee Stadium, to reach a point where we’ll know for sure if it’s the park, the ball, or some combination of both?
To this, he replied:
As for how many games, it’s hard to say exactly, as different people have different thresholds of “certainty”, but I would think it would be a good idea to get at least a couple of complete runs through the Yankees rotation before you can say anything for sure, as you would want some confidence that it isn’t just bad outings or maybe injuries affecting the pitchers. Also, that should give a better cross-section of weather conditions, whereas the first few games might be influenced a lot by a common period of wind/temperature…
However, like anything, the amount of time you need to discern an effect depends on the magnitude of the effect, i.e. the bigger the underlying effect, the sooner it becomes apparent. So, if we go another week with 4-5 homers a game, several of the “questionable” variety, that would push our certainty up considerably…
Very interesting stuff, huh? We’ll have to give this a little more time…say…until the middle of May…to be more sure. But, again, based on what Greg is sharing here, it looks like we should expect to see more homers hit in this Yankee Stadium than we saw in the last one.
My thanks to Greg Rybarczyk for providing this information and for allowing it to be shared here. If you haven’t checked out his work at Hit Tracker…well…you should check it out – and bookmark the site. Greg’s doing incredible work there and it’s a wonderful service for all baseball fans – as it’s cutting-edge, entertaining and educating.