Monday, June 30, 2014

Should Yanks be playing in a house built for Ruth?

Babe Ruth joined the New York Yankees in 1920.  In 1919 Ruth hit 29 home run (HR) in only 432 at bats (AB) to set the season record playing for the Boston Red Sox; Ruth hit 9 HR at home in pre-Ted Williams Fenway Park and 20 on the road.  The Yankees played their home games from 1913 through 1922 in the Polo Grounds in Manhattan.  It was the home park of the New York Giants who along with the Brooklyn Dodgers moved to California after the 1957 season.

Babe Ruth 1921 Polo Grounds
Ruth broke his own home run record three more times: 1920 54, 1921 59, 1927 60.  His team built a park for him in the Bronx for the 1923 season.  It's dimensions favored a lefty power hitter like Ruth.  The conventional wisdom is that Yankee dominance is based on lefty power and to a lesser extent on lefty pitching.  The current Yankee ownership apparently assumed that when they spent a billion dollars to build a new park for the long dead Babe Ruth, one favoring lefty power, even though the vast dimensions in left field had been drastically reduced over the years.

But even in Ruth's time did the Yankees actually get a benefit from their home park, at least in terms of home runs, the basis for the asymmetry of Yankee Stadium?  In 1927 Ruth himself hit 32 of his 60 homers on the road, only 28 at home; slightly better HR Rate on road: 8.97 to 9.04.  But what about all Yankee batters, including Lou Gehrig, and what about the home runs allowed by Yankee pitchers?

Click link to view detailed Yankee team level data.

Yankees 1923-2013:
batters: 6.97% more AB road than home using home as base
pitchers: 2.4% more AB home than road using home as base

home: pitchers 3.67% more AB than batters using batters as base
road: batters 5.41% more AB than pitchers using batters as base

HR rate: AB/HR (lower is better for the batter)

Bat: bat pct dif: Batters HR rate: (home - road) / home
Pit: pit pct dif: Pitchers HR rate: (home - road) / home

Negative HR Rate does not necessarily mean that the Yankees were put at a disadvantage.  Since the Yankees won so much it could be that their players were much better.  For instance, Yankee batters might have hit a lot of home runs and Yankee pitchers allowed few home runs.  Then the difference between the Yankee batters HR Rate and that of the pitchers might have less meaning and that the Yankees simply clobbered the opposition.  However, it could mean that the home park was not the advantage generally assumed and/or that the players were not suited to the park.

The dimensions of Yankee Stadium did change over time, especially after 1973 when it was remodeled.  Even after that the distance in left center was reduced a couple of times in a vain effort to help Dave Winfield.  And, of course, a brand new park was built and then occupied in 2009.  The current incarnation of Yankee Stadium has the same basic structure and dimensions as the previous but with possibly more of an advantage for lefty batters to hit home runs into the short right field porch.  Even non-home run hitters can hit homers more easily, making it more random, which should be a competitive disadvantage to the better team, which the Yankees strive to be.

Ruth years at Yankee Stadium:

In every one of Ruth's seasons Yankee batters had a better HR Rate than Yankee pitchers at Yankee Stadium than on the road.  In 1932, 1933, 1934 both were positive.  However, pitchers were negative in all the other Ruth seasons.  Both batters and pitchers were negative in 1925, 1929, 1930.  The biggest disparity was in 1924: batters positive 42.6%, pitchers negative 234%, difference 277%.  Second biggest disparity: 1923 228%; Yanks won their first World Series in 1923.  Disparity in 1927: 180%.  The gap narrowed as Ruth aged and his impact diminished.  But Yankee Stadium overall had a negative HR Rate during Ruth's years.

Ruth's home/road HR Rate splits 1919-1934:


homehomehomeroadroadroadtottottot
YearHRABAB/HRHRABAB/HRHRABAB/HRhome park
1919920022.222023211.602943214.90Fenway Park
1920292037.002525410.16544578.46Polo Grounds
1921322568.002728510.56595419.17Polo Grounds
19221419614.002121110.053540711.63Polo Grounds
19231924612.952227412.454152012.68Yankee Stadium
19242426010.832226912.234652911.50Yankee Stadium
19251120318.451415611.142535914.36Yankee Stadium
19262324110.482425410.584749510.53Yankee Stadium
1927282539.04322878.97605409.00Yankee Stadium
1928292608.972527611.04545369.93Yankee Stadium
19292121810.382528011.204649810.83Yankee Stadium
1930262449.382327411.914951810.57Yankee Stadium
19312426711.132226712.144653411.61Yankee Stadium
19321923912.58222189.914145711.15Yankee Stadium
1933222149.731224520.423445913.50Yankee Stadium
19341319014.62917519.442236516.59Yankee Stadium
YS2592,83510.952522,97511.815115,81011.37Yankee Stadium
PG756558.737375010.271481,4059.49Polo Grounds

Ruth's Yankee parks HR Rate advantage at home:
YS7.85%
PG17.64%

Ruth played his home games in Yankee Stadium for 12 seasons, of which only the final three were net positive in HR Rate for the Yankee team.  If Yankee owner Jacob Rupert wanted to really help the Babe and the team he would have modeled Yankee Stadium on the Polo Grounds.  But that's all ancient history.  What about more recent dynasties for DiMaggio, Mantle, Jeter?

Ironically, the most positive season for the Yankees was 1938 in the era of righty slugger Joe DiMaggio: net HR Rate 88.6% positive, virtually all by the Yankee batters; Yankee pitchers were almost dead even home/road.  Except for 1940 and 1951, Joltin' Joe personally had better HR Rates on the road.

Yearshome HRhome ABhome AB/HRroad HRroad ABroad AB/HRHRABAB/HRYear
1936828836.002134916.622963721.971936
19371930616.112731511.674662113.501937
19381529619.731730317.823259918.721938
19391223719.751822512.503046215.401939
19401623414.631527418.273150816.391940
19411629218.251424917.793054118.031941
1942830538.131330523.462161029.051942
1946825431.751724914.652550320.121946
1947925228.001128225.642053426.701947
19481529419.602430012.503959415.231948
1949512725.40914516.111427219.431949
1950924226.892328312.303252516.411950
1951823329.13418245.501241534.581951
1483,36022.702133,46116.253616,821265.52



In 1937 with lefty Gehrig still a factor the Yankees had a rare balance: batters positive 22%, pitchers positive 23%.  Both were positive in 1950 and 1951 also.  But as with the Ruth years, Yankee batters are generally positive and Yankee pitchers generally negative (8 of 13 DiMaggio seasons).

The batters were negative 8.1% in 1936 for a net negative 7%.  Pitchers positive only in 1936, 1937, 1938, 1950, 1951.  Batters positive all years except 1936 and 1947 (both negative) when DiMaggio won his third MVP but with only 21 HR.  Net positive impact: 1937, 1938, 1940, 1942, 1946, 1949, 1950 (mostly pitching), 1951.  Eight of 13 DiMaggio years were net positive, better than Ruth years, only the final three of 12.

Mickey Mantle was impacted by Yankee Stadium because he was a switch hitter.  On the road he homered about every 15 AB, both righty and lefty.  But at Yankee Stadium, Mantle's HR Rates were 19.51 righty and 13.12 lefty.  Remember, lower is better.  But because Mantle had only 1,483 AB batting righty in Yankee Stadium and 2,492 AB batting lefty, his home HR Rate was 14.94.  Road 15.27 (15.15 righty, 15.33 lefty).  Mantle 4,883 AB in Yankee Stadium, maybe the second most home AB in one park whose dimensions did not change.  Stan Musial had 5,401 AB in Sportsman's Park St. Louis.

In the Mantle years Yankee batters were generally negative and pitchers generally positive.  Even in the record setting season: 1961 -4.22% 23.74%.  The Yankee team set a major league record with 240 home runs and that was before the designated hitter (DH) had been introduced.  Roger Maris broke Babe Ruth's season record with 61 homers.  And yet Yankee batters hit 112 HR in 2,654 AB (23.70) at home and 128 HR in 2,905 AB (22.70) on the road.  Maris hit 31 road HR but with a better HR Rate at home.

For the three seasons before and after the two in Shea Stadium:

1971-27.84%7.98%
197214.62%28.00%
197337.92%38.71%
1974-20.41%8.05%
1975-8.36%-17.11%
197631.76%-7.19%
1977-9.82%19.84%
197826.47%-6.53%

Derek Jeter era, 1996-2013, during which the Yankees moved into a new version of Yankee Stadium in 2009, largely coincides with the steroid era.  The Yankee batters topped 200 HR 13 times during those years.  They broke the 1961 team record of 240 HR three times:
2012 245 new park
2009 244 new park
2004 242.

Curtis Granderson: home run rate Detroit v. New York.  Friday, December 6, 2013

Curtis Granderson took advantage of playing his home games in Yankee Stadium to hit more home runs.  Rate: At Bats (AB) divided by Home Runs (HR).  Lower is better...

His home rates on the road are fairly consistent, improving with age, which coincided with changing to the Yankees.
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At least 25 road homers but fewer than 50. Could they have hit 50 homers playing only on the road?  Thursday, January 30, 2014

surprise ... Jason Giambi.  Not that he hit 29 HR on the road but that he did it playing his home games in Yankee Stadium, a park which contradicts its reputation for rewarding lefty home run hitters more than expected.
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Granderson led the record setting 2012 team with 43; 41 in 2011.  Giambi hit 41 in his first two Yankee seasons: 2002, 2003.  The previous Yankee to hit at least 40 in consecutive seasons: Mickey Mantle: 40 in 1960, 54 in 1961.  During the Jeter years the Yankee batters returned to taking advantage.

Net average per season, including the two at Shea.  Simply the average of percent difference, not weighted by AB.


max44.69%
min-95.65%
ave2.35%

The Ruth years skew the numbers downward, which is, of course, ironic.  Overall, the Yankees seem to benefit in hitting home runs from their home park.  For the last ten years: new park/old park:

200411.24%
200518.88%
200611.37%
20072.20%
20088.85%
20096.20%
2010-2.49%
2011-1.00%
201220.74%
20133.51%

Yankee management may need to be more careful than ever about getting players who fit their odd park.  Maybe they should have brought back Curtis Granderson.  Maybe there are long term consequences for Masahiro Tanaka, who lost 2-1 to the Red Sox two days ago on two solo homers, the winner a right field short porch special in the ninth inning by righty Mike Napoli.

Tanaka:
home: 9 HR, 238 AB (26.4)
road: 4 HR, 186 AB (46.5) higher is better for a pitcher.

You live by the porch, you die by the porch.