Amos Rusie has allowed the most walks in a season, with 289 allowed in 1890.

Interpreted as:

most single season walks with a minimum of 1 IP per team game by a pitcher

	NAME	BB	SEASON	TM	G	W	L	W%	GS	ERA	SO	CG	SHO	SV	IP	H	ER	R	HR	HBP	GF	IBB	TBF	WP	K/9	BB/9	K/BB	HR/9	K%	BB%	WHIP	BABIP	RA	ERA-	FIP	FIP-	H/9	PRAA
1	Amos Rusie A. Rusie	289	1890	NYN	67	29	34	.460	62	2.56	341	56	4	1	548.2	436	156	300	3	26	5		2,379	36	5.59	4.74	1.18	0.05	14.3	12.1	1.32	.252	4.92	73	3.47	92	7.15	17.7
2	Mark Baldwin M. Baldwin	274	1889	COL	63	27	34	.443	59	3.61	368	54	6	1	513.2	458	206	358	9	20	4		2,275	83	6.45	4.80	1.34	0.16	16.2	12.0	1.43	.280	6.27	100	3.52	98	8.02	-3
3	Amos Rusie A. Rusie	270	1892	NYG	65	32	31	.508	62	2.84	304	59	2	0	541.0	410	171	290	7	12	3		2,314	24	5.06	4.49	1.13	0.12	13.1	11.7	1.26	.234	4.82	89	3.04	96	6.82	5.2
4	Amos Rusie A. Rusie	262	1891	NYG	61	33	20	.623	57	2.55	337	52	6	1	500.1	391	142	244	6	18	4		2,167	17	6.06	4.71	1.29	0.11	15.6	12.1	1.31	.249	4.39	78	3.02	89	7.03	19
5	Mark Baldwin M. Baldwin	249	1890	CHP	58	33	24	.579	56	3.35	206	53	1	0	492.0	494	183	321	10	16	2		2,242	25	3.77	4.55	0.83	0.18	9.2	11.1	1.51	.275	5.87	78	3.96	93	9.04	16.6
6	Jack Stivetts J. Stivetts	232	1891	STL	64	33	22	.600	56	2.86	259	40	3	1	440.0	357	140	237	15	18	8		1,916	28	5.30	4.75	1.12	0.31	13.5	12.1	1.34	.246	4.85	73	3.50	92	7.30	20.1
7	Mark Baldwin M. Baldwin	227	1891	PIT	53	21	28	.429	51	2.76	197	48	2	1	437.2	385	134	278	10	23	2		1,944	24	4.05	4.67	0.87	0.21	10.1	11.7	1.40	.252	5.72	84	3.64	107	7.92	-14.3
8	Phil Knell P. Knell	226	1891	COL	58	28	27	.509	52	2.92	228	47	5	0	462.0	363	150	228	4	54	5		2,017	23	4.44	4.40	1.01	0.08	11.3	11.2	1.27	.239	4.44	84	3.47	103	7.07	-13.4
9	Bob Barr B. Barr	219	1890	ROC	57	28	24	.538	54	3.25	209	52	3	0	493.1	458	178	267	7	14	3		2,152	28	3.81	4.00	0.95	0.13	9.7	10.2	1.37	.265	4.87	88	3.67	106	8.36	-19.2
10	Amos Rusie A. Rusie	218	1893	NYG	56	33	21	.611	52	3.23	208	50	4	1	482.0	451	173	260	15	16	4		2,111	26	3.88	4.07	0.95	0.28	9.9	10.3	1.39	.264	4.85	71	4.24	94	8.42	12
11	Cy Seymour C. Seymour	213	1898	NYG	45	25	19	.568	43	3.18	239	39	4	0	356.2	313	126	199	4	32	2		1,581	19	6.03	5.37	1.12	0.10	15.1	13.5	1.47	.283	5.02	90	3.63	103	7.90	-5.4
12	Gus Weyhing G. Weyhing	212	1889	PHA	54	30	21	.588	53	2.95	213	50	4	0	449.0	382	147	271	15	34	1		1,959	37	4.27	4.25	1.00	0.30	10.9	10.8	1.32	.247	5.43	77	4.13	108	7.66	-15.2
13	Bob Feller B. Feller	208	1938	CLE	39	17	11	.607	36	4.08	240	20	2	1	277.2	225	126	136	13	7	3		1,248	5	7.78	6.74	1.15	0.42	19.2	16.7	1.56	.272	4.41	86	4.13	91	7.29	13
14	Ed Crane E. Crane	208	1890	NYP	43	16	19	.457	35	4.63	116	28	0	0	330.1	323	170	280	12	10	7		1,537	36	3.16	5.67	0.56	0.33	7.5	13.5	1.61	.261	7.63	104	4.67	106	8.80	-4.9
15	Toad Ramsey T. Ramsey	207	1886	LOU	67	38	27	.585	67	2.45	499	66	3	0	588.2	447	160	297	3	12	0		2,477	35	7.63	3.16	2.41	0.05	20.1	8.4	1.11	.253	4.54	71	2.59	76	6.83	54.7
16	Ice Box Chamberlain I. Box Chamberlain	206	1891	PHA	49	22	23	.489	46	4.22	204	44	0	0	405.2	397	190	263	10	12	3		1,822	21	4.53	4.57	0.99	0.22	11.2	11.3	1.49	.278	5.83	113	3.46	96	8.81	8.2
17	Mike Morrison M. Morrison	205	1887	CLE	40	12	25	.324	40	4.92	158	35	0	0	316.2	385	173	341	13	22	1		1,536	62	4.49	5.83	0.77	0.37	10.3	13.3	1.86	.327	9.69	115	4.96	120	10.94	-29.7
18	Nolan Ryan N. Ryan	204	1977	CAL	37	19	16	.543	37	2.77	341	22	4	0	299.0	198	92	110	12	9	0	7	1,272	21	10.26	6.14	1.67	0.36	26.8	16.0	1.34	.263	3.31	72	3.11	79	5.96	27.9
19	Henry Gruber H. Gruber	204	1890	CLP	48	22	23	.489	44	4.27	110	39	1	0	383.1	464	182	352	15	15	4		1,839	36	2.58	4.79	0.54	0.35	6.0	11.1	1.74	.300	8.26	105	4.56	113	10.89	-27.7
20	Ed Crane E. Crane	203	1891	TOT	47	18	22	.450	44	2.97	173	36	2	0	366.2	350	121	242	6	17	3		1,663	21	4.25	4.98	0.85	0.15	10.4	12.2	1.51	.272	5.94	82	3.60	98	8.59	5.6
21	John Clarkson J. Clarkson	203	1889	BSN	73	49	19	.721	72	2.73	284	68	8	1	620.0	589	188	280	16	17	1		2,641	16	4.12	2.95	1.40	0.23	10.8	7.7	1.28	.270	4.06	65	3.49	82	8.55	56.6
22	Nolan Ryan N. Ryan	202	1974	CAL	42	22	16	.579	41	2.89	367	26	3	0	332.2	221	107	127	18	9	1	3	1,392	9	9.93	5.46	1.82	0.49	26.4	14.5	1.27	.255	3.44	85	2.97	84	5.98	20.2
23	Ellsworth Cunningham E. Cunningham	201	1890	TOT	39	12	24	.333	36	5.63	111	35	2	0	319.2	384	200	293	8	13	3		1,562	30	3.13	5.66	0.55	0.23	7.1	12.9	1.83	.306	8.25	135	4.55	110	10.81	-15.1
24	Amos Rusie A. Rusie	200	1894	NYG	54	36	13	.735	50	2.78	195	45	3	1	444.0	426	137	228	10	5	4		1,910	10	3.95	4.05	0.98	0.20	10.2	10.5	1.41	.277	4.62	53	4.61	88	8.64	28.2
25	William Hutchinson W. Hutchinson	199	1890	CHN	71	41	25	.621	66	2.70	289	65	5	2	603.0	505	181	315	20	13	5		2,506	27	4.31	2.97	1.45	0.30	11.5	7.9	1.17	.244	4.70	71	3.44	84	7.54	50.1