lowest era- by a player in a season with at least 148 ip between 1920 to 1937

Between the 1920 and 1937 seasons, Lefty Grove had the best ERA- with 148.0+ innings pitched in a season, with an ERA- of 47 in 1931.

	NAME	ERA-	IP	SEASON	TM	G	W	L	W%	GS	ERA	SO	CG	SHO	SV	H	ER	R	HR	BB	HBP	GF	TBF	WP	K/9	BB/9	K/BB	HR/9	K%	BB%	WHIP	BABIP	RA	FIP	FIP-	H/9	PRAA
1	Lefty Grove L. Grove	47	288.2	1931	PHA	41	31	4	.886	30	2.06	175	27	4	5	249	66	84	10	62	1	10	1,160	2	5.46	1.93	2.82	0.31	15.1	5.3	1.08	.262	2.62	3.01	70	7.76	40.8
2	Dolf Luque D. Luque	50	322.0	1923	CIN	41	27	8	.771	37	1.93	151	28	6	2	279	69	90	2	88	5	4	1,301	4	4.22	2.46	1.72	0.06	11.6	6.8	1.14	.263	2.52	2.94	77	7.80	31
3	Monty Stratton M. Stratton	51	164.2	1937	CWS	22	15	5	.750	21	2.40	69	14	5	0	142	44	55	6	37	2	1	650	0	3.77	2.02	1.86	0.33	10.6	5.7	1.09	.254	3.01	3.39	73	7.76	22.5
4	Carl Hubbell C. Hubbell	52	308.2	1933	NYG	45	23	12	.657	33	1.66	156	22	10	5	256	57	69	6	47	3	11	1,206	3	4.55	1.37	3.32	0.17	12.9	3.9	0.98	.252	2.01	2.53	74	7.46	31.1
5	Lefty Grove L. Grove	53	291.0	1930	PHA	50	28	5	.848	32	2.54	209	22	2	9	273	82	101	8	60	5	17	1,191	2	6.46	1.86	3.48	0.25	17.5	5.0	1.14	.292	3.12	3.09	64	8.44	55.6
6	Lefty Gomez L. Gomez	53	278.1	1937	NYY	34	21	11	.656	34	2.33	194	25	6	0	233	72	88	10	93	1	0	1,148	2	6.27	3.01	2.09	0.32	16.9	8.1	1.17	.262	2.85	3.13	73	7.53	37.4
7	Dazzy Vance D. Vance	53	280.1	1928	BKN	38	22	10	.688	32	2.09	200	24	4	2	226	65	79	11	72	7	5	1,126	1	6.42	2.31	2.78	0.35	17.8	6.4	1.06	.257	2.54	2.83	70	7.26	37.6
8	Dazzy Vance D. Vance	54	258.2	1930	BKN	35	17	15	.531	31	2.61	173	20	4	1	241	75	97	15	55	5	3	1,061	4	6.02	1.91	3.15	0.52	16.3	5.2	1.14	.278	3.38	3.61	75	8.39	35
9	Lefty Grove L. Grove	54	253.1	1936	BSA	35	17	12	.586	30	2.81	130	22	6	2	237	79	90	14	65	4	3	1,049	0	4.62	2.31	2.00	0.50	12.4	6.2	1.19	.267	3.20	3.77	76	8.42	33
10	Johnny Allen J. Allen	56	173.0	1937	CLE	24	15	1	.938	20	2.55	87	14	0	0	157	49	55	4	60	5	4	713	2	4.53	3.12	1.45	0.21	12.2	8.4	1.25	.275	2.86	3.46	77	8.17	19.8
11	Lefty Gomez L. Gomez	56	281.2	1934	NYY	38	26	5	.839	33	2.33	158	25	6	2	223	73	86	12	96	0	5	1,142	3	5.05	3.07	1.65	0.38	13.8	8.4	1.13	.241	2.75	3.57	86	7.13	17.7
12	Mel Harder M. Harder	57	255.1	1934	CLE	44	20	12	.625	29	2.61	91	17	6	5	246	74	97	6	81	7	12	1,072	2	3.21	2.86	1.12	0.21	8.5	7.6	1.28	.271	3.42	3.75	82	8.67	22.8
13	Wilcy Moore W. Moore	57	213.0	1927	NYY	50	19	7	.731	12	2.28	75	6	1	13	185	54	68	3	59	1	30	870	4	3.17	2.49	1.27	0.13	8.6	6.8	1.15	.249	2.87	3.35	85	7.82	13.7
14	Dazzy Vance D. Vance	58	308.1	1924	BKN	35	28	6	.824	34	2.16	262	30	3	0	238	74	89	11	77	9	1	1,221	4	7.65	2.25	3.40	0.32	21.5	6.3	1.02	.263	2.60	2.64	69	6.95	41.3
15	Lefty Grove L. Grove	58	273.0	1935	BSA	35	20	12	.625	30	2.70	121	23	2	1	269	82	105	6	65	3	4	1,137	2	3.99	2.14	1.86	0.20	10.6	5.7	1.22	.279	3.46	3.20	70	8.87	41.5
16	Carl Hubbell C. Hubbell	58	313.0	1934	NYG	49	21	12	.636	35	2.30	118	25	5	8	286	80	100	17	37	2	11	1,255	2	3.39	1.06	3.19	0.49	9.4	2.9	1.03	.249	2.88	3.45	87	8.22	18.2
17	Red Faber R. Faber	58	330.2	1921	CWS	43	25	15	.625	39	2.48	124	32	4	1	293	91	107	10	87	7	4	1,350	5	3.38	2.37	1.43	0.27	9.2	6.4	1.15	.252	2.91	3.60	87	7.97	19.3
18	Carl Hubbell C. Hubbell	59	304.0	1936	NYG	42	26	6	.813	34	2.31	123	25	3	3	265	78	81	7	57	5	6	1,202	3	3.64	1.69	2.16	0.21	10.2	4.7	1.06	.255	2.40	3.37	81	7.85	26.6
19	Bill Walker B. Walker	60	239.1	1931	NYG	37	16	9	.640	28	2.26	121	19	6	5	212	60	78	6	64	3	7	991	2	4.55	2.41	1.89	0.23	12.2	6.5	1.15	.258	2.93	3.27	84	7.97	16.3
20	Ray Kremer R. Kremer	61	226.0	1927	PIT	35	19	8	.704	28	2.47	63	18	3	1	205	62	73	9	53	0	6	927	2	2.51	2.11	1.19	0.36	6.8	5.7	1.14	.244	2.91	3.69	90	8.16	10.9
21	Grover Alexander G. Alexander	61	363.1	1920	CHC	46	27	14	.659	40	1.91	173	33	7	5	335	77	96	8	69	1	6	1,447	3	4.29	1.71	2.51	0.20	12.0	4.8	1.11	.273	2.38	2.66	81	8.30	25
22	Lon Warneke L. Warneke	62	277.0	1932	CHC	35	22	6	.786	32	2.37	106	25	4	0	247	73	84	12	64	2	2	1,117	5	3.44	2.08	1.66	0.39	9.5	5.7	1.12	.252	2.73	3.53	89	8.03	12.7
23	Sheriff Blake S. Blake	62	240.2	1928	CHC	34	17	11	.607	29	2.47	78	16	4	1	209	66	80	4	101	3	5	995	3	2.92	3.78	0.77	0.15	7.8	10.2	1.29	.253	2.99	3.77	92	7.82	9.2
24	Lefty Grove L. Grove	62	258.0	1926	PHA	45	13	13	.500	33	2.51	194	20	1	6	227	72	97	6	101	6	9	1,072	5	6.77	3.52	1.92	0.21	18.1	9.4	1.27	.289	3.38	2.96	73	7.92	31.2
25	Lon Warneke L. Warneke	62	287.1	1933	CHC	36	18	13	.581	34	2.00	133	26	4	1	262	64	83	8	75	3	1	1,175	6	4.17	2.35	1.77	0.25	11.3	6.4	1.17	.266	2.60	3.05	88	8.21	12.8