Erik Kratz was the oldest relief pitcher in 2020. He was 40 years old.

	NAME	AGE	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	H/9
1	Erik Kratz E. Kratz	40	2020	NYY	2	0	0		0	9.00	0	0	0	0	2.0	2	2	2	2	0	1	2	0	9	0	0.00	0.00		9.00	0.0	0.0	1.00	.000	9.00	9.00
2	Oliver Perez O. Perez	38	2020	CLE	21	1	1	.500	0	2.00	14	0	0	1	18.0	13	4	5	0	6	3	2	3	72	0	7.00	3.00	2.33	0.00	19.4	8.3	1.06	.265	2.50	6.50
3	Sergio Romo S. Romo	37	2020	MIN	24	1	2	.333	0	4.05	23	0	0	5	20.0	16	9	9	3	7	3	7	0	87	0	10.35	3.15	3.29	1.35	26.4	8.0	1.15	.255	4.05	7.20
4	Darren O'Day D. O'Day	37	2020	ATL	19	4	0	1.000	0	1.10	22	0	0	0	16.1	8	2	3	1	5	3	1	0	67	0	12.12	2.76	4.40	0.55	32.8	7.5	0.80	.194	1.65	4.41
5	Drew Butera D. Butera	36	2020	COL	1	0	0		0	5.40	1	0	0	0	1.2	3	1	1	0	0	0	1	0	8	0	5.40	0.00		0.00	12.5	0.0	1.80	.429	5.40	16.20
6	Yoshihisa Hirano Y. Hirano	36	2020	SEA	13	0	1	.000	0	5.84	11	0	0	4	12.1	18	8	9	2	8	1	9	0	63	0	8.03	5.84	1.38	1.46	17.5	12.7	2.11	.390	6.57	13.14
7	Craig Stammen C. Stammen	36	2020	SDP	24	4	2	.667	0	5.63	20	0	0	0	24.0	27	15	16	2	4	2	6	0	105	0	7.50	1.50	5.00	0.75	19.0	3.8	1.29	.325	6.00	10.13
8	Edinson Volquez E. Volquez	36	2020	TEX	7	2	1	.667	0	6.35	3	0	0	0	5.2	6	4	4	0	2	1	3	0	26	0	4.76	3.18	1.50	0.00	11.5	7.7	1.41	.300	6.35	9.53
9	Jesse Chavez J. Chavez	36	2020	TEX	18	0	0		0	6.88	13	0	0	0	17.0	20	13	13	6	7	1	5	0	77	0	6.88	3.71	1.86	3.18	16.9	9.1	1.59	.280	6.88	10.59
10	Joakim Soria J. Soria	36	2020	OAK	22	2	2	.500	0	2.82	24	0	0	2	22.1	18	7	8	1	10	0	4	3	96	0	9.67	4.03	2.40	0.40	25.0	10.4	1.25	.279	3.22	7.25
11	Cesar Valdez C. Valdez	35	2020	BAL	9	1	1	.500	0	1.26	12	0	0	3	14.1	7	2	3	0	3	0	7	0	53	1	7.53	1.88	4.00	0.00	22.6	5.7	0.70	.184	1.88	4.40
12	Blake Parker B. Parker	35	2020	PHI	13	3	0	1.000	0	3.21	22	0	0	0	14.0	12	5	7	2	9	0	4	2	63	0	14.14	5.79	2.44	1.29	34.9	14.3	1.50	.333	4.50	7.71
13	Pat Venditte P. Venditte	35	2020	MIA	3	0	0		0	0.00	5	0	0	0	4.1	1	0	0	0	0	2	2	0	15	0	10.38	0.00		0.00	33.3	0.0	0.23	.125	0.00	2.08
14	Mark Melancon M. Melancon	35	2020	ATL	23	2	1	.667	0	2.78	14	0	0	11	22.2	22	7	8	1	7	2	19	3	95	1	5.56	2.78	2.00	0.40	14.7	7.4	1.28	.296	3.18	8.74
15	Will Harris W. Harris	35	2020	WSH	20	0	1	.000	0	3.06	21	0	0	1	17.2	21	6	9	3	9	0	5	0	84	1	10.70	4.58	2.33	1.53	25.0	10.7	1.70	.353	4.58	10.70
16	Andrew Miller A. Miller	35	2020	STL	16	1	1	.500	0	2.77	16	0	0	4	13.0	9	4	4	0	5	3	5	0	55	2	11.08	3.46	3.20	0.00	29.1	9.1	1.08	.290	2.77	6.23
17	Pedro Strop P. Strop	35	2020	CIN	4	0	0		0	3.86	3	0	0	0	2.1	1	1	3	0	6	0	0	0	15	1	11.57	23.14	0.50	0.00	20.0	40.0	3.00	.167	11.57	3.86
18	Daniel Bard D. Bard	35	2020	COL	23	4	2	.667	0	3.65	27	0	0	6	24.2	22	10	10	2	10	3	10	2	106	1	9.85	3.65	2.70	0.73	25.5	9.4	1.30	.313	3.65	8.03
19	Ian Kennedy I. Kennedy	35	2020	KCR	14	0	2	.000	0	10.50	12	0	0	0	12.0	19	14	17	7	4	1	1	1	61	0	9.00	3.00	3.00	5.25	19.7	6.6	1.92	.324	12.75	14.25
20	Josh Tomlin J. Tomlin	35	2020	ATL	12	1	0	1.000	0	2.95	24	0	0	0	18.1	13	6	6	2	4	0	2	1	70	1	11.78	1.96	6.00	0.98	34.3	5.7	0.93	.275	2.95	6.38
21	Tony Watson T. Watson	35	2020	SFG	21	1	0	1.000	0	2.50	15	0	0	2	18.0	13	5	8	3	3	1	4	0	73	0	7.50	1.50	5.00	1.50	20.5	4.1	0.89	.196	4.00	6.50
22	Tyler Clippard T. Clippard	35	2020	MIN	24	2	1	.667	0	2.74	23	0	0	0	23.0	18	7	8	1	4	0	1	0	88	2	9.00	1.57	5.75	0.39	26.1	4.5	0.96	.283	3.13	7.04
23	Junior Guerra J. Guerra	35	2020	ARI	25	1	2	.333	0	3.04	21	0	0	0	23.2	17	8	10	1	15	2	5	2	103	2	7.99	5.70	1.40	0.38	20.4	14.6	1.35	.250	3.80	6.46
24	Brandon Kintzler B. Kintzler	35	2020	MIA	24	2	3	.400	0	2.22	14	0	0	12	24.1	21	6	7	3	11	0	21	3	101	0	5.18	4.07	1.27	1.11	13.9	10.9	1.32	.247	2.59	7.77
25	Yusmeiro Petit Y. Petit	35	2020	OAK	26	2	1	.667	0	1.66	17	0	0	0	21.2	19	4	4	3	5	0	6	0	88	0	7.06	2.08	3.40	1.25	19.3	5.7	1.11	.254	1.66	7.89