Ed Cushman give up the fewest H/9 in a season, with 2.50 per nine innings in 1884.

Interpreted as:

lowest h/9 with a minimum of 1 IP per team game by a player in a season pitcher

	NAME	H/9	SEASON	TM	G	W	L	W%	GS	ERA	SO	CG	SHO	SV	IP	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-	PRAA
1	Ed Cushman E. Cushman	2.50	1884	MIL	4	4	0	1.000	4	1.00	47	4	2	0	36.0	10	4	4	0	3		0		125	1	11.75	0.75	15.67	0.00	37.6	2.4	0.36		1.00	8	0.91	8	17.4
2	Lady Baldwin L. Baldwin	3.71	1884	MIL	2	1	1	.500	2	2.65	21	2	0	0	17.0	7	5	5	0	1		0		61	0	11.12	0.53	21.00	0.00	34.4	1.6	0.47		2.65	20	0.98	9	8.2
3	Trevor Bauer T. Bauer	5.05	2020	CIN	11	5	4	.556	11	1.73	100	2	2	0	73.0	41	14	17	9	17	3	0	1	278	3	12.33	2.10	5.88	1.11	36.0	6.1	0.79	.215	2.10	36	2.87	61	14.1
4	Dinelson Lamet D. Lamet	5.09	2020	SDP	12	3	1	.750	12	2.09	93	0	0	0	69.0	39	16	18	5	20	4	0	0	267	1	12.13	2.61	4.65	0.65	34.8	7.5	0.86	.234	2.35	49	2.47	56	15.1
5	Nolan Ryan N. Ryan	5.26	1972	CAL	39	19	16	.543	39	2.28	329	20	9	0	284.0	166	72	80	14	157	10	0	4	1,154	18	10.43	4.98	2.10	0.44	28.5	13.6	1.14	.236	2.54	79	2.48	83	16.6
6	Luis Tiant L. Tiant	5.30	1968	CLE	34	21	9	.700	32	1.60	264	19	9	0	258.1	152	46	53	16	73	4	0	4	987	3	9.20	2.54	3.62	0.56	26.7	7.4	0.87	.216	1.85	53	2.04	64	33
7	Nolan Ryan N. Ryan	5.31	1991	TEX	27	12	6	.667	27	2.91	203	2	2	0	173.0	102	56	58	12	72	5	0	0	683	8	10.56	3.75	2.82	0.62	29.7	10.5	1.01	.230	3.02	72	2.74	68	24.4
8	Pedro Martinez P. Martinez	5.31	2000	BOS	29	18	6	.750	29	1.74	284	7	4	0	217.0	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	61.5
9	Ed Reulbach E. Reulbach	5.33	1906	CHC	33	19	4	.826	24	1.65	94	20	6	3	218.0	129	40	51	2	92	13	9		842	3	3.88	3.80	1.02	0.08	11.2	10.9	1.01	.198	2.11	62	3.07	111	-7.2
10	Shane Bieber S. Bieber	5.35	2020	CLE	12	8	1	.889	12	1.63	122	0	0	0	77.1	46	14	15	7	21	1	0	0	297	5	14.20	2.44	5.81	0.81	41.1	7.1	0.87	.267	1.75	37	2.06	46	20.5
11	Kenta Maeda K. Maeda	5.40	2020	MIN	11	6	1	.857	11	2.70	80	0	0	0	66.2	40	20	20	9	10	0	0	0	248	0	10.80	1.35	8.00	1.21	32.3	4.0	0.75	.208	2.70	62	2.99	68	10.5
12	Justin Verlander J. Verlander	5.53	2019	HOU	34	21	6	.778	34	2.58	300	2	1	0	223.0	137	64	66	36	42	6	0	0	847	4	12.11	1.70	7.14	1.45	35.4	5.0	0.80	.218	2.66	57	3.26	72	31.5
13	Dutch Leonard D. Leonard	5.57	1914	BSA	36	19	5	.792	25	0.96	176	17	7	3	224.2	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	20.4
14	Blake Snell B. Snell	5.58	2018	TBR	31	21	5	.808	31	1.89	221	0	0	0	180.2	112	38	41	16	64	1	0	2	700	13	11.01	3.19	3.45	0.80	31.6	9.1	0.97	.241	2.04	46	2.94	72	23.1
15	Henry Porter H. Porter	5.65	1884	MIL	6	3	3	.500	6	3.00	71	6	1	0	51.0	32	17	25	1	9		0		200	6	12.53	1.59	7.89	0.18	35.5	4.5	0.80		4.41	23	1.27	11	24.1
16	Max Scherzer M. Scherzer	5.65	2017	WSH	31	16	6	.727	31	2.51	268	2	0	0	200.2	126	56	62	22	55	11	0	2	780	4	12.02	2.47	4.87	0.99	34.4	7.1	0.90	.245	2.78	57	2.89	66	33.2
17	Carl Lundgren C. Lundgren	5.65	1907	CHC	28	18	7	.720	25	1.17	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	-2.3
18	Sid Fernandez S. Fernandez	5.71	1985	NYM	26	9	9	.500	26	2.80	180	3	0	0	170.1	108	53	56	14	80	2	0	3	685	3	9.51	4.23	2.25	0.74	26.3	11.7	1.10	.230	2.96	80	3.08	86	9.6
19	Tommy Byrne T. Byrne	5.74	1949	NYY	32	15	7	.682	30	3.72	129	12	3	0	196.0	125	81	84	11	179	13	2		880	4	5.92	8.22	0.72	0.51	14.7	20.3	1.55	.208	3.86	92	4.86	120	-19
20	Blake Snell B. Snell	5.75	2023	SDP	32	14	9	.609	32	2.25	234	0	0	0	180.0	115	45	47	15	99	3	0	0	742	13	11.70	4.95	2.36	0.75	31.5	13.3	1.19	.256	2.35	54	3.43	79	18
21	Dave McNally D. McNally	5.77	1968	BAL	35	22	10	.688	35	1.95	202	18	5	0	273.0	175	59	67	24	55	10	0	1	1,038	5	6.66	1.81	3.67	0.79	19.5	5.3	0.84	.202	2.21	67	2.76	90	9.5
22	Jose Fernandez J. Fernandez	5.79	2013	MIA	28	12	6	.667	28	2.19	187	0	0	0	172.2	111	42	47	10	58	5	0	5	681	3	9.75	3.02	3.22	0.52	27.5	8.5	0.98	.240	2.45	60	2.72	75	18.1
23	Sandy Koufax S. Koufax	5.79	1965	LAD	43	26	8	.765	41	2.04	382	27	8	2	335.2	216	76	90	26	71	5	2	4	1,297	11	10.24	1.90	5.38	0.70	29.5	5.5	0.86	.234	2.41	63	1.93	61	47.9
24	Russ Ford R. Ford	5.83	1910	NYH	36	26	6	.813	33	1.65	209	29	8	1	299.2	194	55	69	4	70	8	3		1,112	5	6.28	2.10	2.99	0.12	18.8	6.3	0.88	.231	2.07	63	1.88	69	28.3
25	Tim Keefe T. Keefe	5.83	1880	TRO	12	6	6	.500	12	0.86	39	12	0	0	105.0	68	10	27	0	16		0		397	1	3.34	1.37	2.44	0.00	9.8	4.0	0.80		2.31	35	2.25	91	3.6