player lowest era by day of week, min 150 ip, all-time, since 1920

Since 1920, Mariano Rivera has the best ERA when pitching at least 150 innings, with an ERA of 1.39 on Wednesdays.

	NAME	ERA	IP	WEEKDAY	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	H/9
1	Mariano Rivera M. Rivera	1.39	213.2	Wednesday	186	11	5	.688	1	182	0	0	118	129	33	38	6	40	6	168	6	797	1	7.67	1.68	4.55	0.25	22.8	5.0	0.79	.218	1.60	5.43
2	Ron Perranoski R. Perranoski	1.77	157.2	Wednesday	103	13	10	.565	0	102	0	0	27	126	31	40	4	62	1	64	12	643	5	5.82	3.54	1.65	0.23	15.9	9.6	1.19	.257	2.28	7.19
3	Trevor Hoffman T. Hoffman	1.83	162.0	Saturday	151	10	8	.556	0	172	0	0	96	108	33	36	7	39	3	127	8	630	4	9.56	2.17	4.41	0.39	27.3	6.2	0.91	.247	2.00	6.00
4	Dean Chance D. Chance	1.87	207.1	Monday	40	16	8	.667	26	158	10	7	2	163	43	63	10	56	5	8	10	829	3	6.86	2.43	2.82	0.43	19.1	6.8	1.06	.255	2.73	7.08
5	Jon Matlack J. Matlack	1.96	363.1	Saturday	51	25	9	.735	46	252	23	7	2	288	79	95	15	97	3	4	8	1,431	9	6.24	2.40	2.60	0.37	17.6	6.8	1.06	.257	2.35	7.13
6	Hoyt Wilhelm H. Wilhelm	1.98	514.1	Sunday	232	28	21	.571	12	363	6	2	54	387	113	140	24	143	9	139	15	2,042	14	6.35	2.50	2.54	0.42	17.8	7.0	1.03	.242	2.45	6.77
7	Dan Quisenberry D. Quisenberry	1.99	153.2	Tuesday	103	8	9	.471	0	53	0	0	40	150	34	40	4	21	2	88	12	606	0	3.10	1.23	2.52	0.23	8.7	3.5	1.11	.278	2.34	8.79
8	Rich Gossage R. Gossage	2.03	284.1	Tuesday	155	22	11	.667	4	226	4	0	55	212	64	71	13	101	7	110	12	1,140	8	7.15	3.20	2.24	0.41	19.8	8.9	1.10	.251	2.25	6.71
9	Tom Hall T. Hall	2.04	172.0	Sunday	67	9	4	.692	10	167	2	2	5	98	39	53	15	77	2	24	6	692	5	8.74	4.03	2.17	0.78	24.1	11.1	1.02	.193	2.77	5.13
10	Billy Wagner B. Wagner	2.04	154.1	Saturday	147	10	7	.588	0	207	0	0	82	95	35	44	10	59	6	123	3	619	8	12.07	3.44	3.51	0.58	33.4	9.5	1.00	.252	2.57	5.54
11	Jacob deGrom J. deGrom	2.06	253.0	Wednesday	41	15	9	.625	41	311	0	0	0	173	58	59	21	63	4	0	4	980	7	11.06	2.24	4.94	0.75	31.7	6.4	0.93	.262	2.10	6.15
12	Josh Johnson J. Johnson	2.07	173.2	Tuesday	28	8	7	.533	26	164	0	0	0	130	40	46	8	52	6	0	8	692	5	8.50	2.69	3.15	0.41	23.7	7.5	1.05	.264	2.38	6.74
13	Rube Marquard R. Marquard	2.08	173.1	Sunday	27	12	6	.667	20	67	10	2	0	152	40	46	3	28	2	4		683	1	3.48	1.45	2.39	0.16	9.8	4.1	1.04	.256	2.39	7.89
14	Sandy Koufax S. Koufax	2.08	182.0	Monday	27	18	4	.818	23	218	15	3	1	118	42	44	15	57	2	3	6	720	4	10.78	2.82	3.82	0.74	30.3	7.9	0.96	.241	2.18	5.84
15	Roger Wolff R. Wolff	2.08	155.2	Wednesday	26	8	8	.500	16	67	12	3	2	140	36	46	3	35	2	8		630	2	3.87	2.02	1.91	0.17	10.6	5.6	1.12	.262	2.66	8.09
16	Hoyt Wilhelm H. Wilhelm	2.09	159.2	Monday	80	7	9	.438	3	107	0	0	19	116	37	53	9	69	8	48	3	665	8	6.03	3.89	1.55	0.51	16.1	10.4	1.16	.227	2.99	6.54
17	Hyun Jin Ryu H. Jin Ryu	2.09	198.0	Sunday	34	20	3	.870	34	194	1	1	0	171	46	56	13	35	3	0	0	787	1	8.82	1.59	5.54	0.59	24.7	4.4	1.04	.292	2.55	7.77
18	Mark Eichhorn M. Eichhorn	2.16	167.0	Friday	96	14	8	.636	1	120	0	0	7	127	40	45	6	47	5	42	13	667	6	6.47	2.53	2.55	0.32	18.0	7.0	1.04	.247	2.43	6.84
19	Ed Heusser E. Heusser	2.17	166.0	Friday	37	9	9	.500	18	41	9	2	2	154	40	52	7	47	1	9		685	1	2.22	2.55	0.87	0.38	6.0	6.9	1.21	.250	2.82	8.35
20	Dave Dravecky D. Dravecky	2.17	169.2	Sunday	38	12	9	.571	20	103	7	0	3	138	41	56	13	52	3	8	7	684	0	5.46	2.76	1.98	0.69	15.1	7.6	1.12	.244	2.97	7.32
21	Mort Cooper M. Cooper	2.18	219.0	Friday	30	14	9	.609	27	106	16	5	1	168	53	59	11	58	0	3		859	1	4.36	2.38	1.83	0.45	12.3	6.8	1.03	.230	2.42	6.90
22	Dick Hall D. Hall	2.18	177.1	Wednesday	72	15	4	.789	8	106	3	1	16	134	43	45	15	36	2	44		682	0	5.38	1.83	2.94	0.76	15.5	5.3	0.96	.228	2.28	6.80
23	Chris Sale C. Sale	2.19	229.2	Monday	42	17	5	.773	31	252	2	0	1	188	56	63	22	42	12	4	1	901	2	9.88	1.65	6.00	0.86	28.0	4.7	1.00	.290	2.47	7.37
24	Whitey Ford W. Ford	2.21	611.0	Friday	91	46	18	.719	86	393	35	10	1	490	150	184	41	222	3	4		2,482	11	5.79	3.27	1.77	0.60	15.8	8.9	1.17	.246	2.71	7.22
25	Bruce Sutter B. Sutter	2.23	190.0	Friday	109	13	10	.565	0	161	0	0	50	135	47	50	6	55	2	82	16	752	5	7.63	2.61	2.93	0.28	21.4	7.3	1.00	.244	2.37	6.39