best single season era by a pitcher ever red sox 1890 to 2023 minimum 30 innings

Between the 1890 and 2023 seasons, Buck O'Brien had the lowest ERA for the Red Sox with 30.0+ innings pitched in a season, with an ERA of 0.38 in his rookie season in 1911.

	NAME	ERA	IP	SEASON	TM	G	W	L	W%	GS	SO	CG	SHO	SV	H	ER	R	HR	BB	HBP	GF	IBB	TBF	WP	K/9	BB/9	K/BB	HR/9	K%	BB%	WHIP	BABIP	RA	ERA-	FIP	FIP-	H/9	PRAA
1	Buck O'Brien B. O'Brien	0.38	47.2	1911	BSA	6	5	1	.833	5	31	5	2	0	30	2	9	0	21	1	1		189	0	5.85	3.97	1.48	0.00	16.4	11.1	1.07	.221	1.70	11	2.85	88	5.66	2
2	Jonathan Papelbon J. Papelbon	0.92	68.1	2006	BOS	59	4	2	.667	0	75	0	0	35	40	7	8	3	13	1	49	2	257	2	9.88	1.71	5.77	0.40	29.2	5.1	0.78	.224	1.05	20	2.13	48	5.27	17.7
3	Dutch Leonard D. Leonard	0.96	224.2	1914	BSA	36	19	5	.792	25	176	17	7	3	139	24	34	3	60	8	8		842	2	7.05	2.40	2.93	0.12	20.9	7.1	0.89	.229	1.36	36	1.95	70	5.57	20.4
4	Chris Martin C. Martin	1.05	51.1	2023	BOS	55	4	1	.800	0	46	0	0	3	45	6	6	2	8	0	12	3	199	1	8.06	1.40	5.75	0.35	23.1	4.0	1.03	.301	1.05	23	2.43	56	7.89	10.7
5	Koji Uehara K. Uehara	1.09	74.1	2013	BOS	73	4	1	.800	0	101	0	0	21	33	9	10	5	9	1	40	2	265	1	12.23	1.09	11.22	0.61	38.1	3.4	0.57	.188	1.21	26	1.60	41	4.00	19.1
6	Nelson Chittum N. Chittum	1.19	30.1	1959	BOS	21	3	0	1.000	0	12	0	0	0	29	4	9	0	11	0	13	2	124	0	3.56	3.26	1.09	0.00	9.7	8.9	1.32	.287	2.67	29	2.84	69	8.60	4.2
7	Cy Young C. Young	1.26	299.0	1908	BOS	36	21	11	.656	33	150	30	3	2	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
8	Calvin Schiraldi C. Schiraldi	1.41	51.0	1986	BOS	25	4	2	.667	0	55	0	0	9	36	8	8	5	15	1	21	2	198	1	9.71	2.65	3.67	0.88	27.8	7.6	1.00	.254	1.41	33	2.82	69	6.35	7.2
9	Junichi Tazawa J. Tazawa	1.43	44.0	2012	BOS	37	1	1	.500	0	45	0	0	1	37	7	7	1	5	2	13	0	172	0	9.20	1.02	9.00	0.20	26.2	2.9	0.95	.303	1.43	34	1.81	45	7.57	11.1
10	Craig Kimbrel C. Kimbrel	1.43	69.0	2017	BOS	67	5	0	1.000	0	126	0	0	35	33	11	11	6	14	4	51	0	254	5	16.43	1.83	9.00	0.78	49.6	5.5	0.68	.260	1.43	31	1.41	32	4.30	22.7
11	Fritz Coumbe F. Coumbe	1.44	62.1	1914	BSA	17	1	2	.333	5	17	1	0	1	49	10	20	0	16	0	10		237	1	2.45	2.31	1.06	0.00	7.2	6.8	1.04	.240	2.89	54	2.66	96	7.07	0.7
12	Joe Wood J. Wood	1.49	157.1	1915	BSA	25	15	5	.750	16	63	10	3	2	120	26	32	1	44	1	8		600	3	3.60	2.52	1.43	0.06	10.5	7.3	1.04	.242	1.83	52	2.55	88	6.86	6
13	Rich Garces R. Garces	1.55	40.2	1999	BOS	30	5	1	.833	0	33	0	0	2	25	7	9	1	18	0	4	1	164	0	7.30	3.98	1.83	0.22	20.1	11.0	1.06	.214	1.99	32	3.15	68	5.53	6.9
14	Scott Atchison S. Atchison	1.58	51.1	2012	BOS	42	2	1	.667	0	36	0	0	0	42	9	10	2	9	0	7	3	200	2	6.31	1.58	4.00	0.35	18.0	4.5	0.99	.261	1.75	37	2.72	67	7.36	7.7
15	Ryan Brasier R. Brasier	1.60	33.2	2018	BOS	34	2	0	1.000	0	29	0	0	0	19	6	6	2	7	0	5	0	124	1	7.75	1.87	4.14	0.53	23.4	5.6	0.77	.198	1.60	36	2.83	68	5.08	5.1
16	Ray Collins R. Collins	1.62	244.2	1910	BSA	35	13	11	.542	26	109	18	4	1	205	44	73	1	41	1	9		937	1	4.01	1.51	2.66	0.04	11.6	4.4	1.01	.260	2.69	64	2.00	76	7.54	16.9
17	Cy Young C. Young	1.62	371.1	1901	BSA	43	33	10	.767	41	158	38	5	0	324	67	112	6	37	7	2		1,440	2	3.83	0.90	4.27	0.15	11.0	2.6	0.97	.258	2.71	44	2.64	72	7.85	42.6
18	Ernie Shore E. Shore	1.64	247.0	1915	BSA	38	19	8	.704	32	102	17	4	0	207	45	75	3	66	4	3		978	4	3.72	2.40	1.55	0.11	10.4	6.7	1.11	.254	2.73	57	2.59	89	7.54	8.2
19	Joe Wood J. Wood	1.69	196.2	1910	BSA	35	12	13	.480	17	145	14	3	0	155	37	81	3	56	10	13		771	5	6.64	2.56	2.59	0.14	18.8	7.3	1.07	.273	3.71	67	2.05	78	7.09	12.4
20	Rube Foster R. Foster	1.70	211.2	1914	BSA	32	14	8	.636	27	89	17	5	0	164	40	68	2	52	7	2		813	1	3.78	2.21	1.71	0.09	10.9	6.4	1.02	.244	2.89	63	2.55	92	6.97	4.8
21	Pedro Martinez P. Martinez	1.74	217.0	2000	BOS	29	18	6	.750	29	284	7	4	0	128	42	44	17	32	14	0	0	817	1	11.78	1.33	8.88	0.71	34.8	3.9	0.74	.236	1.82	35	2.16	47	5.31	61.5
22	Carl Mays C. Mays	1.74	289.0	1917	BSA	35	22	9	.710	33	91	27	2	0	230	56	81	1	74	14	2		1,129	6	2.83	2.30	1.23	0.03	8.1	6.6	1.05	.241	2.52	69	2.59	98	7.16	0.3
23	Clay Buchholz C. Buchholz	1.74	108.1	2013	BOS	16	12	1	.923	16	96	1	1	0	75	21	23	4	36	1	0	0	416	1	7.98	2.99	2.67	0.33	23.1	8.7	1.02	.254	1.91	42	2.78	71	6.23	13.5
24	Babe Ruth B. Ruth	1.75	323.2	1916	BSA	44	23	12	.657	40	170	23	9	1	230	63	83	0	118	8	3		1,272	3	4.73	3.28	1.44	0.00	13.4	9.3	1.08	.236	2.31	65	2.43	90	6.40	8.8
25	Bud Byerly B. Byerly	1.78	30.1	1958	BOS	18	1	2	.333	0	16	0	0	0	31	6	12	1	7	1	10	3	128	0	4.75	2.08	2.29	0.30	12.5	5.5	1.25	.291	3.56	45	2.64	66	9.20	4.4