Most Total Bases in Age 20 season: top 10.

For single seasons, since 1903, from age 20 to 20, Playing in the AL or NL, in the regular season, requiring Total Bases >= 290, sorted by descending Total Bases.

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

Rk	Player	TB	Season	Age	Team	Lg	G	PA	AB	R	H	1B	2B	3B	HR	RBI	SB	CS	BB	SO	BA	OBP	SLG	OPS	OPS+	GIDP	IBB	Pos
1	Álex Rodríguez	379	1996	20	SEA	AL	146	677	601	141	215	124	54	1	36	123	15	4	59	104	.358	.414	.631	1.045	161	15	1	*6/H
2	Mel Ott	346	1929	20	NYG	NL	150	675	545	138	179	98	37	2	42	151	6	13	113	38	.328	.449	.635	1.084	165		3	*9/48H
3	Ted Williams	344	1939	20	BOS	AL	149	677	565	131	185	99	44	11	31	145	2	1	107	64	.327	.436	.609	1.045	160	10	12	*9
4	Vada Pinson	330	1959	20	CIN	NL	154	706	648	131	205	129	47	9	20	84	21	6	55	98	.316	.371	.509	.880	129	9	3	*8
5	Al Kaline	321	1955	20	DET	AL	152	681	588	121	200	141	24	8	27	102	6	8	82	57	.340	.421	.546	.967	162	13	12	*9
6	Frank Robinson	319	1956	20	CIN	NL	152	668	572	122	166	95	27	6	38	83	8	4	64	95	.290	.379	.558	.936	143	14	7	*7/8H
7	Mike Trout	315	2012	20	LAA	AL	139	639	559	129	182	117	27	8	30	83	49	5	67	139	.326	.399	.564	.963	168	7	4	*87/9H
8	Orlando Cepeda	309	1958	20	SFG	NL	148	644	603	88	188	121	38	4	25	96	15	11	29	84	.312	.342	.512	.854	125	18	7	*3/H
9	Juan Soto	297	2019	20	WSN	NL	150	659	542	110	153	82	32	5	34	110	12	1	108	132	.282	.401	.548	.949	142	11	3	*7
10	Mickey Mantle	291	1952	20	NYY	AL	142	626	549	94	171	104	37	7	23	87	4	1	75	111	.311	.394	.530	.924	162	5	10	*89/5H

Provided by Stathead: Found with Stathead. See Full Results.
Generated 4/6/2026.

Half in 1950s.

Ott: most HR way back in 1929; 2 in TB, 1 in BB.

Reds: 1956 & 1959.

Two in this millennium: Trout, Soto.

None 1960-1995.

Trout highest OPS+; Cepeda lowest.

Mantle fewest GIDP.

Three led league in 2B but none in 3B or HR.

Pinson most AB, Soto fewest.

Ott highest SLG, Pinson lowest.

Trout led league in SB.

Rodriguez barely made it: Born: July 27, 1975 (had to be 20 before July).

Sorted on Days 20 as of June 30 in the age 20 season:

	birth day	age 20 season	Days 20
Ott	Tue, Mar 2, 1909	Sun, Jun 30, 1929	120
Kaline	Wed, Dec 19, 1934	Thu, Jun 30, 1955	193
Soto	Sun, Oct 25, 1998	Sun, Jun 30, 2019	248
Mantle	Tue, Oct 20, 1931	Mon, Jun 30, 1952	254
Cepeda	Fri, Sep 17, 1937	Mon, Jun 30, 1958	286
Williams	Fri, Aug 30, 1918	Fri, Jun 30, 1939	304
Robinson	Sat, Aug 31, 1935	Sat, Jun 30, 1956	304
Pinson	Thu, Aug 11, 1938	Tue, Jun 30, 1959	323
Trout	Wed, Aug 7, 1991	Sat, Jun 30, 2012	328
Rodriguez	Sun, Jul 27, 1975	Sun, Jun 30, 1996	339