worst era in a single season by a team since 1901

Since 1901, the Philadelphia Phillies have the highest ERA by a team in a season, with an ERA of 6.71 in 1930.

	TEAM	ERA	SEASON	G	W%	W	L	GS	SO	CG	SHO	SV	IP	H	ER	R	HR	BB	HBP	IBB	TBF	WP	K/9	BB/9	K/BB	HR/9	K%	BB%	WHIP	BABIP	RA	H/9
1	Phillies	6.71	1930	156	.338	52	102	156	384	54	3	7	1372.2	1,993	1,024	1,199	142	543	33		6,549	23	2.52	3.56	0.71	0.93	5.9	8.3	1.85	.340	7.86	13.07
2	Tigers	6.38	1996	162	.327	53	109	162	957	10	4	22	1432.2	1,699	1,015	1,103	241	784	80	63	6,713	82	6.01	4.93	1.22	1.51	14.3	11.7	1.73	.313	6.93	10.67
3	Browns	6.24	1936	155	.375	57	95	155	399	54	3	13	1348.1	1,776	935	1,064	115	609	47		6,382	44	2.66	4.07	0.66	0.77	6.3	9.5	1.77	.319	7.10	11.85
4	Phillies	6.13	1929	154	.464	71	82	154	369	45	5	24	1348.0	1,743	918	1,036	122	616	39		6,303	21	2.46	4.11	0.60	0.81	5.9	9.8	1.75	.314	6.92	11.64
5	Athletics	6.08	1936	154	.346	53	100	154	405	68	3	11	1352.1	1,645	913	1,045	131	696	24		6,301	67	2.70	4.63	0.58	0.87	6.4	11.0	1.73	.300	6.95	10.95
6	Rockies	6.01	1999	162	.444	72	90	162	1,032	12	1	33	1429.0	1,700	955	1,028	237	737	60	46	6,574	70	6.50	4.64	1.40	1.49	15.7	11.2	1.71	.325	6.47	10.71
7	Browns	6.01	1939	156	.279	43	111	156	516	56	3	4	1371.1	1,724	916	1,035	133	739	29		6,474	32	3.39	4.85	0.70	0.87	8.0	11.4	1.80	.315	6.79	11.31
8	Browns	6.00	1937	156	.299	46	108	156	468	55	2	8	1363.0	1,770	909	1,023	143	653	30		6,371	34	3.09	4.31	0.72	0.94	7.3	10.2	1.78	.320	6.75	11.69
9	Rockies	5.97	2025	162	.265	43	119	162	1,093	0	0	29	1407.1	1,673	933	1,021	251	554	73	19	6,367	60	6.99	3.54	1.97	1.61	17.2	8.7	1.58	.323	6.53	10.70
10	Orioles	5.84	2021	162	.321	52	110	162	1,234	1	1	26	1402.0	1,518	910	956	258	563	68	12	6,252	88	7.92	3.61	2.19	1.66	19.7	9.0	1.48	.305	6.14	9.74
11	Browns	5.80	1938	156	.362	55	97	156	632	71	3	7	1344.2	1,584	867	962	132	737	26		6,222	27	4.23	4.93	0.86	0.88	10.2	11.8	1.73	.309	6.44	10.60
12	Athletics	5.79	1939	153	.362	55	97	153	397	50	6	12	1342.2	1,687	864	1,022	148	579	19		6,248	35	2.66	3.88	0.69	0.99	6.4	9.3	1.69	.301	6.85	11.31
13	Twins	5.76	1995	144	.389	56	88	144	790	7	2	27	1272.2	1,450	815	889	210	533	36	18	5,714	52	5.59	3.77	1.48	1.49	13.8	9.3	1.56	.299	6.29	10.25
14	Rangers	5.71	2001	162	.451	73	89	162	951	4	1	37	1438.1	1,670	913	968	222	596	63	33	6,469	70	5.95	3.73	1.60	1.39	14.7	9.2	1.58	.312	6.06	10.45
15	Twins	5.68	1994	113	.469	53	60	113	602	6	2	29	1005.0	1,197	634	688	153	388	31	20	4,507	43	5.39	3.47	1.55	1.37	13.4	8.6	1.58	.313	6.16	10.72
16	Rockies	5.67	2023	162	.364	59	103	162	1,129	0	0	31	1414.0	1,599	891	957	234	586	86	13	6,316	51	7.19	3.73	1.93	1.49	17.9	9.3	1.55	.319	6.09	10.18
17	Rangers	5.67	2003	162	.438	71	91	162	1,009	4	2	43	1433.1	1,625	903	969	208	603	63	45	6,413	51	6.34	3.79	1.67	1.31	15.7	9.4	1.55	.313	6.08	10.20
18	Royals	5.65	2006	162	.383	62	100	162	904	3	2	35	1426.1	1,648	896	971	213	637	60	45	6,434	85	5.70	4.02	1.42	1.34	14.1	9.9	1.60	.311	6.13	10.40
19	Tigers	5.63	2020	58	.397	23	35	58	444	1	0	11	492.1	511	308	318	91	192	34	2	2,174	18	8.12	3.51	2.31	1.66	20.4	8.8	1.43	.297	5.81	9.34
20	Phillies	5.61	1928	152	.283	43	109	152	402	42	4	13	1346.2	1,664	839	956	108	675	42		6,224	22	2.69	4.51	0.60	0.72	6.5	10.8	1.74	.311	6.39	11.12
21	Orioles	5.59	2019	162	.333	54	108	162	1,248	0	0	27	1443.0	1,544	897	981	305	561	80	11	6,396	75	7.78	3.50	2.22	1.90	19.5	8.8	1.46	.295	6.12	9.63
22	Rockies	5.59	1996	162	.512	83	79	162	932	5	1	34	1422.2	1,597	884	964	198	624	69	19	6,391	66	5.90	3.95	1.49	1.25	14.6	9.8	1.56	.306	6.10	10.10
23	Rockies	5.59	2020	60	.433	26	34	60	393	1	0	16	526.1	579	327	353	83	205	40	5	2,335	29	6.72	3.51	1.92	1.42	16.8	8.8	1.49	.307	6.04	9.90
24	Red Sox	5.58	2020	60	.400	24	36	60	537	0	0	14	524.0	587	325	351	98	252	31	4	2,389	28	9.22	4.33	2.13	1.68	22.5	10.5	1.60	.332	6.03	10.08
25	Rockies	5.56	2019	162	.438	71	91	162	1,264	1	1	28	1448.2	1,576	895	958	270	589	57	33	6,423	63	7.85	3.66	2.15	1.68	19.7	9.2	1.49	.308	5.95	9.79