Junior Caminero and Chuck Klein: at least 40 Home Runs in first two "full" seasons.

Junior Caminero is an active player with the first place Tampa Bay Rays. He is an MVP candidate for 2026.

Chuck Klein played 1928 - 1944. He was NL MVP in 1932 and finished second in 1931 and 1933. He is in the Hall of Fame.

A full season here is meant as a common sense definition, not a rookie of the year definition, which changed multiple times:

https://www.baseball-reference.com/awards/roy.shtml

Rookie of the Year (Jackie Robinson Award)

...  In 1971, the standard was adjusted to 130 at-bats, 50 innings pitched, or 45 days of non-September service time. Since 2020, days on the roster in September count towards service time...

________________________

https://www.sports-reference.com/stathead/tiny/pXdHC

For single seasons, since 1920, Playing in the AL or NL, in the regular season, requiring Home Runs >= 40, sorted by descending Player Name.

380 40 HR seasons as of this date!

Fewest AB for 40 HR:

Rk	Player	AB	HR	Season	Age	Team	Lg	G	PA
1	Barry Bonds	373	45	2004	39	SFG	NL	147	617
2	Barry Bonds	390	45	2003	38	SFG	NL	130	550
3	Henry Aaron	392	40	1973	39	ATL	NL	120	465
4	Barry Bonds	403	46	2002	37	SFG	NL	143	612
5	Mark McGwire	423	52	1996	32	OAK	AL	130	548
6	J.D. Martinez	432	45	2017	29	ARI,DET	AL,NL	119	489
7	Ken Griffey Jr.	433	40	1994	24	SEA	AL	111	493
8	Mike Trout	438	40	2022	30	LAA	AL	119	499
9	Matt Williams	445	43	1994	28	SFG	NL	112	483
10	Joey Gallo	449	41	2017	23	TEX	AL	145	532

I cruised through the long list looking for possible matches: young and consecutive seasons. I looked at a batter's personal data if he seemed to be a possible match. I almost missed Chuck Klein. Here are a few who got my attention followed by details on Caminero and Klein.

Eddie Mathews:

Season	Age	Team	Lg	WAR	G	PA	AB	R	H	2B	3B	HR
1952	20	BSN	NL	2.4	145	593	528	80	128	23	5	25
1953	21	MLN	NL	8.1	157	681	579	110	175	31	8	47
1954	22	MLN	NL	7.7	138	601	476	96	138	21	4	40
1955	23	MLN	NL	7.2	141	616	499	108	144	23	5	41

Willie McCovey (1959 Rookie of the Year!):

Season	Age	Team	Lg	WAR	G	PA	AB	R	H	2B	3B	HR
1959	21	SFG	NL	3.1	52	219	192	32	68	9	5	13
1960	22	SFG	NL	1.7	101	307	260	37	62	15	3	13
1961	23	SFG	NL	2.7	106	374	328	59	89	12	3	18
1962	24	SFG	NL	1.9	91	262	229	41	67	6	1	20
1963	25	SFG	NL	6.5	152	627	564	103	158	19	5	44
1964	26	SFG	NL	-0.1	130	434	364	55	80	14	1	18

Alex Rodriguez:

Season	Age	Team	Lg	WAR	G	PA	AB	R	H	2B	3B	HR
1994	18	SEA	AL	-0.3	17	59	54	4	11	0	0	0
1995	19	SEA	AL	-0.4	48	149	142	15	33	6	2	5
1996	20	SEA	AL	9.4	146	677	601	141	215	54	1	36
1997	21	SEA	AL	5.7	141	638	587	100	176	40	3	23
1998	22	SEA	AL	8.5	161	748	686	123	213	35	5	42
1999	23	SEA	AL	4.8	129	572	502	110	143	25	0	42
2000	24	SEA	AL	10.4	148	672	554	134	175	34	2	41
2001	25	TEX	AL	8.3	162	732	632	133	201	34	1	52
2002	26	TEX	AL	8.8	162	725	624	125	187	27	2	57
2003	27	TEX	AL	8.4	161	715	607	124	181	30	6	47

Manny Ramirez:

Season	Age	Team	Lg	WAR	G	PA	AB	R	H	2B	3B	HR
1993	21	CLE	AL	-0.8	22	55	53	5	9	1	0	2
1994	22	CLE	AL	1.6	91	336	290	51	78	22	0	17
1995	23	CLE	AL	3.0	137	571	484	85	149	26	1	31
1996	24	CLE	AL	4.2	152	647	550	94	170	45	3	33
1997	25	CLE	AL	4.6	150	651	561	99	184	40	0	26
1998	26	CLE	AL	5.3	150	663	571	108	168	35	2	45
1999	27	CLE	AL	7.3	147	640	522	131	174	34	3	44

Albert Pujols:

Season	Age	Team	Lg	WAR	G	PA	AB	R	H	2B	3B	HR
2001	21	STL	NL	6.6	161	676	590	112	194	47	4	37
2002	22	STL	NL	5.5	157	675	590	118	185	40	2	34
2003	23	STL	NL	8.7	157	685	591	137	212	51	1	43
2004	24	STL	NL	8.5	154	692	592	133	196	51	2	46
2005	25	STL	NL	8.4	161	700	591	129	195	38	2	41
2006	26	STL	NL	8.5	143	634	535	119	177	33	1	49

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Finally, Junior Caminero and Chuck Klein:

Junior Caminero:

Season	Age	Team	Lg	WAR	G	PA	AB	R	H	2B	3B	HR
2023	19	TBR	AL	0.0	7	36	34	4	8	1	0	1
2024	20	TBR	AL	0.7	43	177	165	15	41	9	1	6
2025	21	TBR	AL	4.3	154	653	602	93	159	28	0	45
2026	22	TBR	AL	5.6	155	677	592	96	164	24	1	41
4 Yr	4 Yr	4 Yr	4 Yr	10.6	359	1543	1393	208	372	62	2	93
162	162	162	162	4.8	162	696	629	94	168	28	1	42

Provided by Baseball-Reference.com: View Original Table
Generated 9/22/2026.

Chuck Klein:

Hall of Fame: Inducted as Player in 1980. (Voted by Veterans Committee)
   View Chuck Klein's Page at the Baseball Hall of Fame (plaque, photos, videos).

Season	Age	Team	Lg	WAR	G	PA	AB	R	H	2B	3B	HR
1928	23	PHI	NL	2.1	64	275	253	41	91	14	4	11
1929	24	PHI	NL	5.1	149	679	616	126	219	45	6	43
1930	25	PHI	NL	6.5	156	722	648	158	250	59	8	40
1931	26	PHI	NL	5.2	148	657	594	121	200	34	10	31
1932	27	PHI	NL	7.5	154	711	650	152	226	50	15	38
1933	28	PHI	NL	8.0	152	667	606	101	223	44	7	28

Klein played a few games through 1944 but didn't lead the league in anything after 1933.

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