Citi Field Is NOT Where HR Go To Die

Bryan CurleyCorrespondent IJanuary 4, 2010

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Much has been made of the Mets’ new home and with good reason. We saw the usually power prolific sluggers from Queens struggle all season with Daniel Murphy leading the entire team in HR with 12. Only four other Mets finished the season with double-digit HR (Wright, Beltran, Sheffield, Francoeur), and they all finished with exactly 10.

So what gives? Isn’t it common knowledge now that Citi Field is where HR go to die? Well yes, everyone “knows” that, but it may not be that simple. The ballpark, while not exactly a hitter’s haven, is really not as terrible as most think. In fact, statistics actually show that it played as a neutral park last season.

It is important to note that it is difficult to accurately characterize a ballpark based on only one year of data, however in Citi Field’s case we can definitely draw one conclusion: based on 2009 batted-ball data, Citi Field did not deserve the poor reputation that it has been given. While there are still many seasons to play until we can conclusively know the park’s trends, after six months of baseball data, the results may shock you.

Citi Field v. Shea Stadium

Before we dive into data, let’s just take a look at the two ballparks’ dimensions.

It is also important to note that Citi Field does have higher fences than Shea Stadium did. Citi Field is also a bit shorter down the lines and in dead center but has larger power alleys. This means that dead-pull hitters shouldn’t struggle too much in comparison to Shea Stadium, but those that like to use the alleys or hit for power to all fields should see a noticeable drop.

This is the case with David Wright’s infamous 2009 season. Wright is a notoriously disciplined hitter who uses the whole field, and as a result saw different results when hitting toward the deeper power alleys. I’m not going to reiterate the Wright debate since it was described very thoroughly by Fangraphs, so check that out.

For more information on Citi Field’s dimensions, check out this New York Times insert.

Raw HR Data

Now it’s time to look at some numbers.

All combined opponents in 2009 hit 81 HR at Citi Field, which would have been tied for 15th in baseball. This combines every team that played at Citi Field in 2009, both the big slugging teams like Philadelphia and the light hitting teams like San Francisco. But hold on, the Mets played Philadelphia a lot more than they played San Francisco. Shouldn’t that mean more than just 81 HR should have been hit at Citi Field? True, the Phillies were one of the best HR-hitting teams last season, but the rest of the NL East wasn’t quite as good.

With three of the Mets’ NL East opponents sitting well below the league average in HR, we can conclude that there certainly wasn’t a constant influx of HR hitting behemoths entering Citi Field last season, thus the 81 HR hit by road teams (T-15 in MLB) shows that the visitors did not struggle mightily.

Analyzing Park Factors

It’s difficult to start talking about hitter- or pitcher-friendly ballparks without stumbling across Park Factors. Essentially, they’re a ratio of production at a given ballpark versus production away from that ballpark. When analyzing HR Park Factors (HRPF), we’re looking at whether a ballpark is more conducive to hitting HR than the MLB average or not. It is represented by the following formula:

HRPF = ((HRHome + HRAHome)/#GamesHome)/((HRAway + HRAAway)/#GamesAway)

In this formula, HRHome is the home team’s HR at home, HRAHome is the HR allowed by the home team at home, HRAway is the HR hit by the home team on the road, and HRAAway is the HR allowed by the home team on the road. As you can see, it is simply a ratio of all HR hit at the home team’s ballpark to all HR hit when the “home” team is at a visitor’s ballpark. When analyzing HRPF, anything over 1.000 indicates a more hitter-friendly park and anything under 1.000 indicates a more pitcher-friendly park.

So how did Citi Field compare to Shea Stadium?

HRPF is obviously the HR Park Factor for the stadiums each season, Mets H HR is the number of HR the Mets hit at home, Mets A HR is the number of HR the Mets hit on the road, and Mets H/Mets A is the ratio of Mets H HR to Mets A HR. The greater this number, the higher the percentage the of HR the Mets hit at home, and vice versa. The last column, P HR/Mets H/A is a ratio of HRPF to Mets H/Mets A. This tells us how much of the HRPF is attributed to the road teams visiting Citi and Shea. Numbers less than 1.000 show that the road teams hit fewer HR at Citi/Shea than they did at their home ballparks and vice versa.

When looking at the data, one number jumps out before all the rest. In 2009, Citi Field had a HRPF of 1.057, indicating that despite all of the negative press it received, it actually played as slightly HR friendly. This HRPF was good for 12th best in baseball, putting it in the top half of all ballparks. As we know, Shea Stadium had a reputation as a pitcher’s park anyway, and the HR numbers support that. Only once in its final five seasons did Shea behave like a HR hitters park (2008), and the other four seasons it was very pitcher friendly, ranking an average of 24.25 in HRPF.

Like I said earlier, this does not mean that Citi Field is a HR hitter’s ballpark because you cannot conclude that after one year of ballpark data, however the numbers seem to indicate that Citi Field may continue to play as a fairly neutral park.

Is This Just A Fluke Year For Citi Field?

Now that we’ve seen how Citi Field behaved last season, is this just a fluke year or will it continue to show the same statistical trends? In truth, this is impossible to know without more games being played, but when making decisions on whether or not players will rebound, we need to take our best guesses.

Using HR data from Hit Tracker Online, I looked at all of the HR hit in baseball last season and compared them to all of the HR hit at Citi Field. For reference, HR are classified into four categories: No Doubts, Just Enough, Lucky, and Standard. A HR can be classified as multiple categories, for example it can be both Just Enough and Lucky, but it cannot be both Just Enough and No Doubt (obviously). All Standard HR were left out since we can characterize the HR data with the other three.

Looking at the numbers, we see that the MLB average for No Doubts was 20.4% versus Citi Field’s 13.1%. This shows that Citi Field had far fewer No Doubt HR as compared to the MLB average. We also see that Citi Field had more Just Enough and Lucky HR than the MLB average.

It is difficult to imagine the Citi Field HR data moving farther away from league averages, therefore it is likely that similar trends should be seen in 2010. This seems to indicate, though, that Citi Field is harder to hit HR in than the average ballpark, but we saw that opponents were tied for 15th in road HR when hitting at Citi.

There is another factor to account for. We haven’t looked at the quality of the Mets pitchers yet.

Based on these numbers we see the Mets finished 8th in baseball in HR allowed in 2009, but there was a disparity between their MLB ranks for HR allowed at home and on the road with the Mets actually allowing more HR at home. Although this data is represented in the HRPF, looking at the Mets pitchers specifically gives us a broader view of the ballpark’s trends because it accounts for a wider range of players (i.e. all visiting players all season) as opposed to looking at the Mets HR hitting data, which only accounts for the players on the Mets’ roster.

Putting Everything Together

We’ve looked at a lot of data, so when everything is put together, what do we see?

  • Overall, Citi Field is larger than Shea Stadium and has higher walls, but it is actually shorter down the lines.
  • In 2009, road teams hit 81 HR at Citi Field, which would have tied for 15th in baseball with the Chicago White Sox if all road teams were considered one team.
  • In 2009, the Mets hit three more HR at home than they did on the road.
  • HRPF data suggests that Citi Field played slightly HR-friendly in 2009, finishing 12th best among all ballparks.
  • Citi Field had a higher rate of Just Enough and Lucky HR in 2009 than the MLB average, and fewer No Doubt HR.
  • Mets pitchers allowed fewer HR on the road than they did at home in 2009.

All of the data suggests that Citi Field actually played as a fairly HR neutral ballpark in 2009, and because we cannot reasonably expect the rates of Just Enough HR, Lucky HR, and No Doubt HR to deviate further from the league average, it is reasonable to expect that Citi Field will behave in a similar manner in 2010.

As I have said before, it is impossible to draw any definite conclusions from only one year of data, however the numbers indicate that Citi Field wrongfully earned a reputation as a place where HR go to die based mainly on the Mets’ struggles last season (David Wright in particular). In comparison to Shea Stadium, despite the changes in dimensions, it figures to play fairly similar, however more data is of course needed.

What Does This Mean For Your Fantasy Team?

It is probably unreasonable to expect Wright to return to his normal 30-HR ways. His hitting style does not fit Citi Field as he likes to use all fields, and it is estimated that he lost eight HR due to Citi Field’s new dimension last season. Players that tend to pull the ball more, particularly right handed batters (JASON BAY!) should not suffer very much though. In fact, I will state right now that given Citi Field’s dimensions and the players possibly batting in front of Bay (namely Reyes, Wright, Beltran, Murphy), it is likely they will see some of their HR turned into doubles or triples, thus putting runners on base for the right-handed, pull-hitting Bay to drive in. I expect Bay to do quite well in Citi Field.


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