Early Home Run rates for past sluggers: DiMaggio, Mantle, Mays, Aaron, ...

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Sanchez, Judge, Bellinger have better Home Run rates in major league than minor. Saturday, June 24, 2017

The Juiced Ball Is Back
New testing suggests the baseball is at least partially responsible for MLB’s huge homer spike
by Ben Lindbergh, Staff Writer, The Ringer June 14, 2017

... the home run explosion hadn’t yet extended to the upper levels of the minor leagues, which use balls manufactured in China that differ from the Costa Rica–made MLB ball
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There is talk that Aaron Judge, 25 year old Yankee rookie, will soon break the Yankee rookie record of 29 Home Runs held by Joe DiMaggio. The talk should turn to Judge breaking the record of any Yankee:
60 HR by Babe Ruth in 154 games in 1927
61 HR by Roger Maris in 162 games in 1961.

The same could be said about Cody Bellinger, Dodger rookie, who might become the first Dodger in either Brooklyn or Los Angeles to hit 50 homers in a season. This despite Bellinger joining the team April 25, 2017 in Dodger game 21. Bellinger did not homer in his first four games, 13 AB, making his HR rate even more remarkable.

This post examines the HR rate of some sluggers from those thrilling days of yesteryear ... plus Mike Trout.

Using the baseball-reference.com definition of rookie, I found 26 players, including Trout, who hit at least 30 HR as a rookie. Here are the ten who hit at least 35 homers as a rookie:

Rk	Player	HR	Year	Age	Tm	Lg	G	PA	AB	R	H	2B	3B	RBI	BB	IBB	SO	HBP	SH	SF	GDP	SB	CS	BA	OBP	SLG	OPS	Pos
1	Mark McGwire (RoY-1st)	49	1987	23	OAK	AL	151	641	557	97	161	28	4	118	71	8	131	5	0	8	6	1	1	.289	.370	.618	.987	*3/59H
2	Frank Robinson (RoY-1st)	38	1956	20	CIN	NL	152	667	572	122	166	27	6	83	64	7	95	20	8	4	14	8	4	.290	.379	.558	.936	*7/8H
3	Wally Berger	38	1930	24	BSN	NL	151	628	555	98	172	27	14	119	54		69	4	12			3		.310	.375	.614	.990	*7/H
4	Albert Pujols (RoY-1st)	37	2001	21	STL	NL	161	676	590	112	194	47	4	130	69	6	93	9	1	7	21	1	3	.329	.403	.610	1.013	5379/HD
5	Al Rosen	37	1950	26	CLE	AL	155	668	554	100	159	23	4	116	100		72	10	4		27	5	7	.287	.405	.543	.948	*5/H
6	Jose Abreu (RoY-1st)	36	2014	27	CHW	AL	145	622	556	80	176	35	2	107	51	15	131	11	0	4	14	3	1	.317	.383	.581	.964	*3D/H
7	Mike Piazza (RoY-1st)	35	1993	24	LAD	NL	149	602	547	81	174	24	2	112	46	6	86	3	0	6	10	3	4	.318	.370	.561	.932	*2/H3
8	Ron Kittle (RoY-1st)	35	1983	25	CHW	AL	145	570	520	75	132	19	3	100	39	8	150	8	0	3	10	8	3	.254	.314	.504	.818	*7/HD8
9	Rudy York	35	1937	23	DET	AL	104	417	375	72	115	18	3	101	41		52	0	1			3	2	.307	.375	.651	1.026	*25/H3
10	Hal Trosky	35	1934	21	CLE	AL	154	685	625	117	206	45	9	142	58		49	2	0			2	2	.330	.388	.598	.987	*3

Since it's really tedious and somewhat open to interpretation to determine a player's last minor league season, the details will be limited to about ten players who seemed most interesting. Note that some played in the minors during their major league rookie season, including Mickey Mantle, Willie Mays and Mike Trout. For them, a previous minor league season was used.

For each slugger, the table below shows HR Rate (AB/HR (lower is better)) for last minor, rookie, most Home Runs in a major league season.

As a rookie, only Mark McGwire approached the HR rates of rookies Gary Sanchez in 2016 (10.05) or Judge and Bellinger in 2017, both below 10.

	last	last	last
	minor	minor	minor	rookie	rookie	rookie	rookie	most	most	most	most
	AB	HR	AB/HR	year	AB	HR	AB/HR	year	AB	HR	AB/HR
DiMaggio	679	34	19.97	1936	637	29	21.97	1937	621	46	13.50
Mantle	519	26	19.96	1951	341	13	26.23	1961	514	54	9.52
Mays	306	4	76.50	1951	464	20	23.20	1965	558	52	10.73
Aaron	574	22	26.09	1954	468	13	36.00	1971	495	47	10.53
Robinson	243	12	20.25	1956	572	38	15.05	1966	576	49	11.76
McGwire	475	23	20.65	1987	557	49	11.37	1998	509	70	7.27
Bonds	254	13	19.54	1986	413	16	25.81	2001	476	73	6.52
Trout	353	13	27.15	2012	559	30	18.63	2015	575	41	14.02

Most reasonable people would not think that either McGwire or Barry Bonds were using performance enhancing drugs (PED) in their rookie seasons.