Roy Face has won the most games by a relief pitcher in a season, with 18 wins in 1959.

Interpreted as:

most wins by a player in a season in relief pitcher

	NAME	W	SEASON	TM	L	W%	G	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	H/9
1	Roy Face R. Face	18	1959	PIT	1	.947	57	0	2.60	69	0	0	10	93.1	91	27	28	5	25	1	47	8	381	4	6.65	2.41	2.76	0.48	18.1	6.6	1.24	.306	2.70	8.78
2	Bill Campbell B. Campbell	17	1976	MIN	5	.773	78	0	3.01	115	0	0	20	167.2	145	56	63	9	62	5	68	11	703	7	6.17	3.33	1.85	0.48	16.4	8.8	1.23	.266	3.38	7.78
3	John Hiller J. Hiller	17	1974	DET	14	.548	59	0	2.64	134	0	0	13	150.0	127	44	51	10	62	3	52	19	633	7	8.04	3.72	2.16	0.60	21.2	9.8	1.26	.276	3.06	7.62
4	Tom Johnson T. Johnson	16	1977	MIN	7	.696	71	0	3.13	87	0	0	15	146.2	152	51	57	11	47	5	54	8	630	10	5.34	2.88	1.85	0.68	13.8	7.5	1.36	.294	3.50	9.33
5	Dick Radatz D. Radatz	16	1964	BOS	9	.640	79	0	2.29	183	0	0	29	157.0	103	40	44	13	58	7	67	9	634	1	10.49	3.32	3.16	0.75	28.9	9.1	1.03	.241	2.52	5.90
6	Ron Perranoski R. Perranoski	16	1963	LAD	3	.842	69	0	1.67	75	0	0	21	129.0	112	24	30	7	43	4	47	14	541	4	5.23	3.00	1.74	0.49	13.9	7.9	1.20	.255	2.09	7.81
7	Jim Konstanty J. Konstanty	16	1950	PHN	7	.696	74	0	2.55	57	0	0	22	152.0	108	43	50	11	51	0	62		603	2	3.38	3.02	1.12	0.65	9.5	8.5	1.05	.200	2.96	6.39
8	Dale Murray D. Murray	15	1975	MON	8	.652	63	0	3.96	43	0	0	9	111.1	134	49	59	0	39	3	40	10	499	2	3.48	3.15	1.10	0.00	8.6	7.8	1.55	.324	4.77	10.83
9	Mike Marshall M. Marshall	15	1974	LAD	12	.556	106	0	2.42	143	0	0	21	208.1	191	56	66	9	56	1	83	1	857	5	6.18	2.42	2.55	0.39	16.7	6.5	1.19	.281	2.85	8.25
10	Eddie Fisher E. Fisher	15	1965	CWS	7	.682	82	0	2.40	90	0	0	24	165.1	118	44	51	13	43	2	60	8	646	10	4.90	2.34	2.09	0.71	13.9	6.7	0.97	.211	2.78	6.42
11	Dick Radatz D. Radatz	15	1963	BOS	6	.714	66	0	2.04	162	0	0	23	132.1	94	30	31	9	51	5	58	12	541	5	11.02	3.47	3.18	0.61	29.9	9.4	1.10	.271	2.11	6.39
12	Luis Arroyo L. Arroyo	15	1961	NYY	5	.750	65	0	2.19	87	0	0	29	119.0	83	29	34	5	49	3	54	8	484	4	6.58	3.71	1.78	0.38	18.0	10.1	1.11	.229	2.57	6.28
13	Hoyt Wilhelm H. Wilhelm	15	1952	NYG	3	.833	71	0	2.43	107	0	0	11	159.1	127	43	60	12	56	5	32		646	3	6.04	3.16	1.91	0.68	16.6	8.7	1.15	.247	3.39	7.17
14	Mace Brown M. Brown	15	1938	PIT	8	.652	49	0	3.62	51	0	0	5	124.1	140	50	62	6	44	0	32		547	3	3.69	3.18	1.16	0.43	9.3	8.0	1.48	.300	4.49	10.13
15	Ryan Yarbrough R. Yarbrough	14	2018	TBR	4	.778	32	0	3.72	106	0	0	0	118.2	110	49	52	15	42	6	3	5	505	0	8.04	3.19	2.52	1.14	21.0	8.3	1.28	.283	3.94	8.34
16	Roger McDowell R. McDowell	14	1986	NYM	9	.609	75	0	3.02	65	0	0	22	128.0	107	43	48	4	42	3	52	5	524	3	4.57	2.95	1.55	0.28	12.4	8.0	1.16	.251	3.38	7.52
17	Mark Eichhorn M. Eichhorn	14	1986	TOR	6	.700	69	0	1.72	166	0	0	10	157.0	105	30	32	8	45	7	38	14	612	2	9.52	2.58	3.69	0.46	27.1	7.4	0.96	.251	1.83	6.02
18	Jim Slaton J. Slaton	14	1983	MIL	6	.700	46	0	4.33	38	0	0	5	112.1	112	54	57	12	56	3	26	5	490	3	3.04	4.49	0.68	0.96	7.8	11.4	1.50	.262	4.57	8.97
19	Mark Clear M. Clear	14	1982	BOS	9	.609	55	0	3.00	109	0	0	14	105.0	92	35	39	11	61	7	44	6	467	1	9.34	5.23	1.79	0.94	23.3	13.1	1.46	.290	3.34	7.89
20	Ron Davis R. Davis	14	1979	NYY	2	.875	44	0	2.85	43	0	0	9	85.1	84	27	29	5	28	1	21	9	357	1	4.54	2.95	1.54	0.53	12.0	7.8	1.31	.282	3.06	8.86
21	Mike Marshall M. Marshall	14	1973	MON	11	.560	92	0	2.66	124	0	0	31	179.0	163	53	62	10	75	4	73	11	747	8	6.23	3.77	1.65	0.50	16.6	10.0	1.33	.287	3.12	8.20
22	Mike Marshall M. Marshall	14	1972	MON	8	.636	65	0	1.78	95	0	0	18	116.0	82	23	26	3	47	2	56	7	465	8	7.37	3.65	2.02	0.23	20.4	10.1	1.11	.248	2.02	6.36
23	Frank Linzy F. Linzy	14	1969	SFG	9	.609	58	0	3.64	62	0	0	11	116.1	129	47	57	5	38	3	39	15	515	8	4.80	2.94	1.63	0.39	12.0	7.4	1.44	.305	4.41	9.98
24	Phil Regan P. Regan	14	1966	LAD	1	.933	65	0	1.62	88	0	0	21	116.2	85	21	24	6	24	0	48	9	446	4	6.79	1.85	3.67	0.46	19.7	5.4	0.93	.241	1.85	6.56
25	Stu Miller S. Miller	14	1965	BAL	7	.667	67	0	1.89	104	0	0	24	119.1	87	25	26	5	32	1	55	10	462	1	7.84	2.41	3.25	0.38	22.5	6.9	1.00	.256	1.96	6.56