Aroldis Chapman had the best ERA by a relief pitcher with 42.0+ innings pitched this season, with an ERA of 1.17.

Interpreted as:

best era rp, min 42 ip this regular season

	NAME	ERA	IP	SEASON	TM	G	W	L	W%	GS	SO	CG	SHO	SV	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	Aroldis Chapman A. Chapman	1.17	61.1	2025	BOS	67	5	3	.625	0	85	0	0	32	28	8	9	3	15	0	43	0	228	6	12.47	2.20	5.67	0.44	37.3	6.6	0.70	.200	1.32	4.11
2	Edwin Díaz E. Díaz	1.63	66.1	2025	NYM	62	6	3	.667	0	98	0	0	28	37	12	14	4	21	8	48	0	258	7	13.30	2.85	4.67	0.54	38.0	8.1	0.87	.260	1.90	5.02
3	Abner Uribe A. Uribe	1.67	75.1	2025	MIL	75	3	2	.600	0	90	0	0	7	51	14	18	4	27	6	15	2	298	5	10.75	3.23	3.33	0.48	30.2	9.1	1.04	.275	2.15	6.09
4	Andrés Muñoz A. Muñoz	1.73	62.1	2025	SEA	64	3	3	.500	0	83	0	0	38	36	12	18	2	28	4	47	3	254	7	11.98	4.04	2.96	0.29	32.7	11.0	1.03	.248	2.60	5.20
5	Randy Rodríguez R. Rodríguez	1.78	50.2	2025	SFG	50	3	5	.375	0	67	0	0	4	34	10	12	4	11	4	15	0	198	2	11.90	1.95	6.09	0.71	33.8	5.6	0.89	.268	2.13	6.04
6	Braydon Fisher B. Fisher	1.85	48.2	2025	TOR	51	7	0	1.000	0	61	0	0	0	28	10	10	2	18	3	12	1	193	0	11.28	3.33	3.39	0.37	31.6	9.3	0.95	.239	1.85	5.18
7	Jason Adam J. Adam	1.93	65.1	2025	SDP	65	8	4	.667	0	70	0	0	0	50	14	18	4	25	3	4	3	270	3	9.64	3.44	2.80	0.55	25.9	9.3	1.15	.274	2.48	6.89
8	Matt Svanson M. Svanson	1.94	60.1	2025	STL	39	4	0	1.000	0	68	0	0	0	33	13	14	3	20	4	10	0	234	1	10.14	2.98	3.40	0.45	29.1	8.5	0.88	.216	2.09	4.92
9	Drew Pomeranz D. Pomeranz	1.94	46.1	2025	CHC	53	2	2	.500	0	53	0	0	1	36	10	12	5	13	5	11	1	190	1	10.29	2.53	4.08	0.97	27.9	6.8	1.06	.272	2.33	6.99
10	Tyler Rogers T. Rogers	1.98	77.1	2025	TOT	81	4	6	.400	0	48	0	0	0	66	17	20	4	7	1	13	0	299	0	5.59	0.81	6.86	0.47	16.1	2.3	0.94	.259	2.33	7.68
11	Mike Vasil M. Vasil	2.00	90.0	2025	CWS	44	5	3	.625	0	71	0	0	4	60	20	24	5	46	6	17	5	371	4	7.10	4.60	1.54	0.50	19.1	12.4	1.18	.226	2.40	6.00
12	Josh Hader J. Hader	2.05	52.2	2025	HOU	48	6	2	.750	0	76	0	0	28	29	12	16	8	16	2	41	1	206	2	12.99	2.73	4.75	1.37	36.9	7.8	0.85	.202	2.73	4.96
13	Jhoan Duran J. Duran	2.06	70.0	2025	TOT	72	7	6	.538	0	80	0	0	32	58	16	19	3	19	3	55	4	287	3	10.29	2.44	4.21	0.39	27.9	6.6	1.10	.302	2.44	7.46
14	Riley O'Brien R. O'Brien	2.06	48.0	2025	STL	42	3	1	.750	0	45	0	0	6	33	11	13	2	22	7	15	2	199	3	8.44	4.13	2.05	0.38	22.6	11.1	1.15	.252	2.44	6.19
15	JoJo Romero J. Romero	2.07	61.0	2025	STL	65	4	6	.400	0	55	0	0	8	47	14	21	2	29	2	16	5	255	2	8.11	4.28	1.90	0.30	21.6	11.4	1.25	.269	3.10	6.93
16	Adrian Morejon A. Morejon	2.08	73.2	2025	SDP	75	13	6	.684	0	70	0	0	3	49	17	23	2	17	0	9	3	286	2	8.55	2.08	4.12	0.24	24.5	5.9	0.90	.239	2.81	5.99
17	Brad Keller B. Keller	2.10	68.2	2025	CHC	67	4	2	.667	0	73	0	0	3	45	16	18	4	22	6	12	0	273	1	9.57	2.88	3.32	0.52	26.7	8.1	0.98	.244	2.36	5.90
18	Danny Coulombe D. Coulombe	2.14	42.0	2025	TOT	54	2	1	.667	0	41	0	0	2	30	10	10	3	18	0	10	0	171	1	8.79	3.86	2.28	0.64	24.0	10.5	1.14	.248	2.14	6.43
19	Carmen Mlodzinski C. Mlodzinski	2.15	50.1	2025	PIT	22	4	4	.500	0	53	0	0	0	44	12	14	3	11	3	7	0	204	4	9.48	1.97	4.82	0.54	26.0	5.4	1.09	.306	2.50	7.87
20	Anthony Bender A. Bender	2.16	50.0	2025	MIA	51	3	5	.375	0	42	0	0	4	32	12	13	3	21	2	12	2	204	1	7.56	3.78	2.00	0.54	20.6	10.3	1.06	.213	2.34	5.76
21	Dennis Santana D. Santana	2.18	70.1	2025	PIT	70	4	5	.444	0	60	0	0	16	44	17	18	5	17	3	34	0	270	0	7.68	2.18	3.53	0.64	22.2	6.3	0.87	.211	2.30	5.63
22	Sean Newcomb S. Newcomb	2.19	70.0	2025	TOT	43	2	2	.500	0	64	0	0	2	62	17	21	4	20	4	11	2	286	2	8.23	2.57	3.20	0.51	22.4	7.0	1.17	.299	2.70	7.97
23	Shawn Armstrong S. Armstrong	2.19	70.0	2025	TEX	69	4	2	.667	0	68	0	0	9	39	17	19	4	19	6	22	0	270	3	8.74	2.44	3.58	0.51	25.2	7.0	0.83	.202	2.44	5.01
24	Ronny Henriquez R. Henriquez	2.22	73.0	2025	MIA	69	7	1	.875	0	98	0	0	7	53	18	23	8	27	4	9	2	303	2	12.08	3.33	3.63	0.99	32.3	8.9	1.10	.271	2.84	6.53
25	Aaron Ashby A. Ashby	2.23	64.2	2025	MIL	42	5	2	.714	0	73	0	0	3	54	16	16	3	24	4	9	0	264	6	10.16	3.34	3.04	0.42	27.7	9.1	1.21	.319	2.23	7.52