Since 1920, Jakie May has the fewest home runs allowed / 9 when pitching at least 1000 innings, with 3.56.

Interpreted as:

lowest hr/9 by a player since 1920 with 1000+ ip

	NAME	HR/9	IP	HR	G	W	L	W%	GS	ERA	SO	CG	SHO	SV	H	ER	R	BB	HBP	GF	IBB	TBF	WP	K/9	BB/9	K/BB	K%	BB%	WHIP	BABIP	RA	ERA-	FIP	FIP-	H/9	PRAA
1	Jakie May J. May	3.56	1254.2	32	338	64	77	.454	124	3.96	628	56	6	19	1,368	552	648	450	58	126		5,492	24	4.50	3.23	1.40	11.4	8.2	1.45	.309	4.65	99	3.61	91	9.81	49.3
2	Jake Miller J. Miller	3.78	1069.2	34	200	60	58	.508	139	4.09	305	58	8	2	1,260	486	582	340	37	32		4,731	1	2.57	2.86	0.90	6.4	7.2	1.50	.305	4.90	94	3.96	92	10.60	39.7
3	Charlie Robertson C. Robertson	4.22	1003.0	38	165	49	79	.383	140	4.43	309	59	6	1	1,144	494	568	377	17	18		4,444	16	2.77	3.38	0.82	7.0	8.5	1.52	.299	5.10	111	4.06	101	10.27	-7
4	Sherry Smith S. Smith	4.56	1271.0	41	236	67	76	.469	139	3.70	208	88	8	15	1,471	522	643	271	28	65		5,460	10	1.47	1.92	0.77	3.8	5.0	1.37	.291	4.55	91	3.80	94	10.42	34.1
5	Bill Doak B. Doak	4.67	1268.2	42	228	82	68	.547	172	3.38	385	66	14	10	1,330	477	596	384	27	36		5,394	15	2.73	2.72	1.00	7.1	7.1	1.35	.283	4.23	91	3.75	100	9.44	-2.7
6	Joe Oeschger J. Oeschger	4.67	1091.1	42	224	51	72	.415	121	4.24	256	56	10	3	1,241	514	605	380	40	67		4,760	29	2.11	3.13	0.67	5.4	8.0	1.49	.297	4.99	116	4.14	113	10.23	-59.3
7	Greg Minton G. Minton	4.78	1130.2	43	710	59	65	.476	7	3.10	479	0	0	150	1,082	389	452	483	16	415	131	4,810	56	3.81	3.84	0.99	10.0	10.0	1.38	.274	3.60	86	3.70	101	8.61	-3.2
8	Rube Marquard R. Marquard	4.78	1000.1	43	176	52	60	.464	130	3.93	341	47	6	2	1,130	437	541	256	11	29		4,291	16	3.07	2.30	1.33	7.9	6.0	1.39	.299	4.87	106	3.65	97	10.17	5.6
9	Al Javery A. Javery	4.89	1142.2	44	205	53	74	.417	147	3.80	470	61	15	5	1,164	483	569	452	17	36		4,972	10	3.70	3.56	1.04	9.5	9.1	1.41	.281	4.48	108	3.43	97	9.17	10.9
10	Mace Brown M. Brown	4.89	1075.1	44	387	76	57	.571	55	3.46	435	18	2	48	1,125	414	502	388	7	206		4,636	26	3.64	3.25	1.12	9.4	8.4	1.41	.287	4.20	90	3.72	94	9.42	28.1
11	Bob Klinger B. Klinger	5.11	1089.2	46	265	66	61	.520	130	3.68	357	48	7	23	1,153	445	525	358	20	83		4,705	23	2.95	2.96	1.00	7.6	7.6	1.39	.282	4.34	99	3.62	96	9.52	18.9
12	Virgil Barnes V. Barnes	5.11	1092.0	46	204	61	59	.508	133	3.63	274	58	7	10	1,186	441	521	292	8	32		4,631	9	2.26	2.41	0.94	5.9	6.3	1.35	.284	4.29	94	3.88	99	9.77	1
13	Al Hollingsworth A. Hollingsworth	5.22	1520.1	47	315	70	104	.402	185	3.99	608	78	7	15	1,642	674	788	587	14	79		6,703	39	3.60	3.47	1.04	9.1	8.8	1.47	.293	4.66	107	3.59	95	9.72	32.6
14	Roger McDowell R. McDowell	5.56	1050.0	50	723	70	70	.500	2	3.30	524	0	0	159	1,045	385	454	410	28	430	98	4,517	37	4.49	3.51	1.28	11.6	9.1	1.39	.284	3.89	87	3.72	97	8.96	12.5
15	Ron Perranoski R. Perranoski	5.56	1174.2	50	737	79	74	.516	1	2.79	687	0	0	178	1,097	364	442	468	24	458	121	5,023	28	5.26	3.59	1.47	13.7	9.3	1.33	.276	3.39	82	3.17	93	8.40	30.6
16	Johnny Humphries J. Humphries	5.56	1002.0	50	211	52	63	.452	111	3.78	317	49	9	12	1,024	421	498	373	26	55		4,342	11	2.85	3.35	0.85	7.3	8.6	1.39	.272	4.47	104	3.77	105	9.20	-20.9
17	Ken Holloway K. Holloway	5.56	1160.0	50	285	64	52	.552	110	4.40	293	43	4	18	1,370	567	684	397	37	100		5,146	13	2.27	3.08	0.74	5.7	7.7	1.52	.302	5.31	105	4.22	101	10.63	-4.3
18	Gary Lavelle G. Lavelle	5.67	1085.0	51	745	80	77	.510	3	2.93	769	0	0	136	1,004	353	413	440	13	399	126	4,604	19	6.38	3.65	1.75	16.7	9.6	1.33	.286	3.43	80	3.13	88	8.33	54.8
19	Terry Forster T. Forster	5.67	1105.2	51	614	54	65	.454	39	3.23	791	5	0	127	1,034	397	454	457	24	318	63	4,700	46	6.44	3.72	1.73	16.8	9.7	1.35	.291	3.70	88	3.08	83	8.42	73.5
20	Johnny Murphy J. Murphy	5.78	1045.0	52	415	93	53	.637	40	3.50	378	17	0	107	985	406	464	444	5	293		4,471	15	3.26	3.82	0.85	8.5	9.9	1.37	.260	4.00	84	4.10	101	8.48	-6.7
21	Stan Coveleski S. Coveleski	5.89	1933.2	53	274	133	89	.599	253	3.20	558	137	21	9	2,041	688	851	510	18	16		8,171	21	2.60	2.37	1.09	6.8	6.2	1.32	.283	3.96	78	3.57	88	9.50	97.7
22	Percy Jones P. Jones	5.89	1026.0	53	251	53	57	.482	114	4.34	381	49	8	8	1,137	495	588	494	40	88		4,611	20	3.34	4.33	0.77	8.3	10.7	1.59	.298	5.16	106	4.53	110	9.97	-49.4
23	Dutch Ruether D. Ruether	5.89	1800.0	53	257	115	86	.572	233	3.75	585	131	14	8	1,959	750	882	627	53	20		7,825	20	2.93	3.14	0.93	7.5	8.0	1.44	.293	4.41	98	3.84	100	9.80	-5.9
24	Benny Frey B. Frey	6	1160.0	54	256	57	82	.410	127	4.50	179	49	7	7	1,415	580	668	263	12	88		5,046	18	1.39	2.04	0.68	3.5	5.2	1.45	.300	5.18	113	4.17	102	10.98	-15
25	George Mogridge G. Mogridge	6	1348.0	54	232	86	79	.521	164	3.63	399	82	12	11	1,488	543	651	365	41	53		5,786	14	2.66	2.44	1.09	6.9	6.3	1.37	.291	4.35	93	3.83	98	9.93	5.1