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:

	home	home	home	road	road	road	tot	tot	tot
Year	HR	AB	AB/HR	HR	AB	AB/HR	HR	AB	AB/HR	home park
1919	9	200	22.22	20	232	11.60	29	432	14.90	Fenway Park
1920	29	203	7.00	25	254	10.16	54	457	8.46	Polo Grounds
1921	32	256	8.00	27	285	10.56	59	541	9.17	Polo Grounds
1922	14	196	14.00	21	211	10.05	35	407	11.63	Polo Grounds
1923	19	246	12.95	22	274	12.45	41	520	12.68	Yankee Stadium
1924	24	260	10.83	22	269	12.23	46	529	11.50	Yankee Stadium
1925	11	203	18.45	14	156	11.14	25	359	14.36	Yankee Stadium
1926	23	241	10.48	24	254	10.58	47	495	10.53	Yankee Stadium
1927	28	253	9.04	32	287	8.97	60	540	9.00	Yankee Stadium
1928	29	260	8.97	25	276	11.04	54	536	9.93	Yankee Stadium
1929	21	218	10.38	25	280	11.20	46	498	10.83	Yankee Stadium
1930	26	244	9.38	23	274	11.91	49	518	10.57	Yankee Stadium
1931	24	267	11.13	22	267	12.14	46	534	11.61	Yankee Stadium
1932	19	239	12.58	22	218	9.91	41	457	11.15	Yankee Stadium
1933	22	214	9.73	12	245	20.42	34	459	13.50	Yankee Stadium
1934	13	190	14.62	9	175	19.44	22	365	16.59	Yankee Stadium
YS	259	2,835	10.95	252	2,975	11.81	511	5,810	11.37	Yankee Stadium
PG	75	655	8.73	73	750	10.27	148	1,405	9.49	Polo Grounds

Ruth's Yankee parks HR Rate advantage at home:

YS	7.85%
PG	17.64%

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.

Years	home HR	home AB	home AB/HR	road HR	road AB	road AB/HR	HR	AB	AB/HR	Year
1936	8	288	36.00	21	349	16.62	29	637	21.97	1936
1937	19	306	16.11	27	315	11.67	46	621	13.50	1937
1938	15	296	19.73	17	303	17.82	32	599	18.72	1938
1939	12	237	19.75	18	225	12.50	30	462	15.40	1939
1940	16	234	14.63	15	274	18.27	31	508	16.39	1940
1941	16	292	18.25	14	249	17.79	30	541	18.03	1941
1942	8	305	38.13	13	305	23.46	21	610	29.05	1942
1946	8	254	31.75	17	249	14.65	25	503	20.12	1946
1947	9	252	28.00	11	282	25.64	20	534	26.70	1947
1948	15	294	19.60	24	300	12.50	39	594	15.23	1948
1949	5	127	25.40	9	145	16.11	14	272	19.43	1949
1950	9	242	26.89	23	283	12.30	32	525	16.41	1950
1951	8	233	29.13	4	182	45.50	12	415	34.58	1951
	148	3,360	22.70	213	3,461	16.25	361	6,821	265.52

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%
1972	14.62%	28.00%
1973	37.92%	38.71%
1974	-20.41%	8.05%
1975	-8.36%	-17.11%
1976	31.76%	-7.19%
1977	-9.82%	19.84%
1978	26.47%	-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.

max	44.69%
min	-95.65%
ave	2.35%

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:

2004	11.24%
2005	18.88%
2006	11.37%
2007	2.20%
2008	8.85%
2009	6.20%
2010	-2.49%
2011	-1.00%
2012	20.74%
2013	3.51%

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.