Between the 1900 and 1909 seasons, Mordecai Brown had the best ERA in a season, with an ERA of 1.04 in 1906.

Interpreted as:

smallest era with a minimum of 1 IP per team game by a player in one season in 00's

	NAME	ERA	SEASON	TM	G	W	L	W%	GS	SO	CG	SHO	SV	IP	H	ER	R	HR	BB	HBP	GF	TBF	WP	K/9	BB/9	K/BB	HR/9	K%	BB%	WHIP	BABIP	RA	ERA-	FIP	FIP-	H/9	PRAA
1	Mordecai Brown M. Brown	1.04	1906	CHC	36	26	6	.813	32	144	27	9	3	277.1	198	32	56	1	61	4	4	1,044	2	4.67	1.98	2.36	0.03	13.8	5.8	0.93	.236	1.82	39	2.08	75	6.43	21.1
2	Christy Mathewson C. Mathewson	1.14	1909	NYG	37	25	6	.806	33	149	26	8	2	275.1	192	35	57	2	36	0	4	998	4	4.87	1.18	4.14	0.07	14.9	3.6	0.83	.234	1.86	44	1.62	61	6.28	31.7
3	Jack Pfiester J. Pfiester	1.15	1907	CHC	30	14	9	.609	22	90	13	3	0	195.0	143	25	61	1	48	5	5	745	2	4.15	2.22	1.88	0.05	12.1	6.4	0.98	.236	2.82	47	2.14	81	6.60	10.6
4	Addie Joss A. Joss	1.16	1908	CLE	42	24	11	.686	35	130	29	9	2	325.0	232	42	77	2	30	2	6	1,209	6	3.60	0.83	4.33	0.06	10.8	2.5	0.81	.220	2.13	49	1.68	76	6.42	19.3
5	Carl Lundgren C. Lundgren	1.17	1907	CHC	28	18	7	.720	25	84	21	7	0	207.0	130	27	42	0	92	2	3	795	2	3.65	4.00	0.91	0.00	10.6	11.6	1.07	.211	1.83	48	2.73	104	5.65	-2.3
6	Cy Young C. Young	1.26	1908	BOS	36	21	11	.656	33	150	30	3	2	299.0	230	42	68	1	37	1	3	1,116	4	4.52	1.11	4.05	0.03	13.4	3.3	0.89	.247	2.05	52	1.52	67	6.92	25.4
7	Christy Mathewson C. Mathewson	1.28	1905	NYG	43	31	9	.775	37	206	32	8	3	338.2	252	48	85	4	64	1	6	1,294	6	5.47	1.70	3.22	0.11	15.9	4.9	0.93	.243	2.26	42	2.03	69	6.70	34.9
8	Jack Taylor J. Taylor	1.29	1902	CHO	37	23	11	.676	34	88	34	8	1	333.2	273	48	86	2	45	12	3	1,278	10	2.37	1.21	1.96	0.05	6.9	3.5	0.95	.240	2.32	49	2.73	98	7.36	0.6
9	Mordecai Brown M. Brown	1.31	1909	CHC	50	27	9	.750	34	172	32	8	7	342.2	246	50	78	1	53	7	15	1,280	9	4.52	1.39	3.25	0.03	13.4	4.1	0.87	.234	2.05	51	1.78	68	6.46	32.4
10	Mordecai Brown M. Brown	1.39	1907	CHC	34	20	6	.769	27	107	20	6	3	233.0	180	36	51	2	40	6	7	861	4	4.13	1.55	2.68	0.08	12.4	4.6	0.94	.252	1.97	56	1.97	75	6.95	17.2
11	Harry Krause H. Krause	1.39	1909	PHA	32	18	8	.692	21	139	16	7	0	213.0	151	33	49	2	49	13	8	801	2	5.87	2.07	2.84	0.08	17.4	6.1	0.94	.249	2.07	58	1.91	82	6.38	9.5
12	Ed Walsh E. Walsh	1.41	1909	CWS	31	15	11	.577	28	127	20	8	2	230.1	166	36	52	0	50	4	3	871	4	4.96	1.95	2.54	0.00	14.6	5.7	0.94	.241	2.03	61	1.82	81	6.49	10.3
13	Ed Walsh E. Walsh	1.42	1908	CWS	66	40	15	.727	49	269	42	11	6	464.0	343	73	111	2	56	9	16	1,755	10	5.22	1.09	4.80	0.04	15.3	3.2	0.86	.240	2.15	63	1.42	67	6.65	34.2
14	Ed Reulbach E. Reulbach	1.42	1905	CHC	34	18	14	.563	29	152	28	5	1	291.2	208	46	71	1	73	18	5	1,124	5	4.69	2.25	2.08	0.03	13.5	6.5	0.96	.235	2.19	48	2.46	85	6.42	14
15	Orval Overall O. Overall	1.42	1909	CHC	38	20	11	.645	32	205	23	9	3	285.0	204	45	66	1	80	8	6	1,116	11	6.47	2.53	2.56	0.03	18.4	7.2	1.00	.247	2.08	55	1.75	67	6.44	27.8
16	Christy Mathewson C. Mathewson	1.43	1908	NYG	56	37	11	.771	44	259	34	11	5	390.2	281	62	85	5	42	3	9	1,469	2	5.97	0.97	6.17	0.12	17.6	2.9	0.83	.238	1.96	61	1.29	52	6.47	52.4
17	Mordecai Brown M. Brown	1.47	1908	CHC	44	29	9	.763	31	123	27	9	5	312.1	214	51	64	1	49	5	12	1,153	6	3.54	1.41	2.51	0.03	10.7	4.2	0.84	.218	1.84	63	1.87	75	6.17	21.5
18	Rube Waddell R. Waddell	1.48	1905	PHA	46	27	10	.730	34	287	27	7	0	328.2	231	54	86	5	90	10	11	1,257	10	7.86	2.46	3.19	0.14	22.8	7.2	0.98	.261	2.35	55	1.89	69	6.33	31.2
19	Jack Pfiester J. Pfiester	1.51	1906	CHC	31	20	8	.714	29	153	20	4	0	250.2	173	42	63	3	63	13	2	966	4	5.49	2.26	2.43	0.11	15.8	6.5	0.94	.232	2.26	57	2.21	80	6.21	15.4
20	Doc White D. White	1.52	1906	CWS	28	18	6	.750	24	95	20	7	0	219.1	160	37	47	2	38	5	4	816	5	3.90	1.56	2.50	0.08	11.6	4.7	0.90	.234	1.93	59	2.21	90	6.57	4.9
21	George McQuillan G. McQuillan	1.53	1908	PHN	48	23	17	.575	42	114	32	7	2	359.2	263	61	88	1	91	6	6	1,367	5	2.85	2.28	1.25	0.03	8.3	6.7	0.98	.227	2.20	66	2.31	95	6.58	4.5
22	Howie Camnitz H. Camnitz	1.56	1908	PIT	38	16	9	.640	26	118	17	3	2	236.2	182	41	76	6	69	5	10	942	2	4.49	2.62	1.71	0.23	12.5	7.3	1.06	.237	2.89	66	2.37	95	6.92	3.2
23	Barney Pelty B. Pelty	1.59	1906	SLA	34	16	11	.593	30	92	25	4	2	260.2	189	46	77	1	59	18	4	995	8	3.18	2.04	1.56	0.03	9.2	5.9	0.95	.228	2.66	61	2.60	104	6.53	-3.7
24	Addie Joss A. Joss	1.59	1904	CLE	25	14	10	.583	24	83	20	5	0	192.1	160	34	51	0	30	7	1	741	3	3.88	1.40	2.77	0.00	11.2	4.0	0.99	.258	2.39	62	2.13	86	7.49	7.4
25	Ed Walsh E. Walsh	1.60	1907	CWS	56	24	18	.571	46	206	37	5	4	422.1	341	75	120	3	87	8	10	1,622	14	4.39	1.85	2.37	0.06	12.7	5.4	1.01	.256	2.56	67	1.97	88	7.27	9.9