who has the best era during the playoffs while playing at least 20 games

John Rocker had the best ERA in the postseason when pitching in 20+ games, with an ERA of 0.00.

	NAME	ERA	G	W	L	W%	GS	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	John Rocker J. Rocker	0.00	20	2	0	1.000	0	26	0	0	3	20.2	10	0	2	0	8	0	5	2	80	2	11.32	3.48	3.25	0.00	32.5	10.0	0.87	.217	0.87	4.35
2	Chad Bradford C. Bradford	0.39	24	0	0		0	13	0	0	0	23.1	18	1	1	0	6	2	2	3	88	0	5.01	2.31	2.17	0.00	14.8	6.8	1.03	.269	0.39	6.94
3	Mariano Rivera M. Rivera	0.70	96	8	1	.889	0	110	0	0	42	141.0	86	11	13	2	21	3	78	4	527	3	7.02	1.34	5.24	0.13	20.9	4.0	0.76	.215	0.83	5.49
4	Jeremy Affeldt J. Affeldt	0.86	33	2	0	1.000	0	20	0	0	0	31.1	14	3	3	1	8	2	4	2	111	2	5.74	2.30	2.50	0.29	18.0	7.2	0.70	.163	0.86	4.02
5	Santiago Casilla S. Casilla	0.92	25	1	0	1.000	0	20	0	0	4	19.2	15	2	3	0	5	2	8	1	82	3	9.15	2.29	4.00	0.00	24.4	6.1	1.02	.273	1.37	6.86
6	Andrew Miller A. Miller	0.93	29	2	1	.667	0	54	0	0	1	38.2	20	4	4	3	13	3	3	2	148	1	12.57	3.03	4.15	0.70	36.5	8.8	0.85	.227	0.93	4.66
7	Kelvin Herrera K. Herrera	1.26	22	2	0	1.000	0	38	0	0	0	28.2	21	4	5	0	10	0	0	0	115	0	11.93	3.14	3.80	0.00	33.0	8.7	1.08	.313	1.57	6.59
8	Scott Eyre S. Eyre	1.32	24	0	0		0	7	0	0	0	13.2	18	2	3	0	3	0	2	3	61	0	4.61	1.98	2.33	0.00	11.5	4.9	1.54	.353	1.98	11.85
9	Clay Carroll C. Carroll	1.39	22	4	2	.667	0	22	0	0	2	32.1	24	5	5	1	13	0	8	4	129	0	6.12	3.62	1.69	0.28	17.1	10.1	1.14	.247	1.39	6.68
10	Tyler Matzek T. Matzek	1.48	20	4	0	1.000	0	38	0	0	0	24.1	16	4	4	1	7	0	1	1	94	1	14.05	2.59	5.43	0.37	40.4	7.4	0.95	.313	1.48	5.92
11	Alan Embree A. Embree	1.66	31	1	0	1.000	0	13	0	0	0	21.2	16	4	5	0	5	1	6	2	84	0	5.40	2.08	2.60	0.00	15.5	6.0	0.97	.246	2.08	6.65
12	Seranthony Domínguez S. Domínguez	1.75	25	4	0	1.000	0	34	0	0	1	25.2	16	5	6	1	9	1	7	0	103	5	11.92	3.16	3.78	0.35	33.0	8.7	0.97	.259	2.10	5.61
13	Wade Davis W. Davis	1.80	30	4	0	1.000	1	57	0	0	8	40.0	29	8	9	5	18	0	14	0	160	2	12.83	4.05	3.17	1.13	35.6	11.3	1.18	.300	2.03	6.53
14	Brusdar Graterol B. Graterol	1.85	25	0	2	.000	0	16	0	0	1	24.1	15	5	6	0	6	2	2	0	96	0	5.92	2.22	2.67	0.00	16.7	6.3	0.86	.208	2.22	5.55
15	Alex Vesia A. Vesia	1.86	26	2	0	1.000	0	23	0	0	1	19.1	13	4	4	2	11	1	2	0	81	1	10.71	5.12	2.09	0.93	28.4	13.6	1.24	.250	1.86	6.05
16	Pedro Strop P. Strop	1.86	22	1	0	1.000	0	14	0	0	0	19.1	9	4	4	1	7	4	2	0	75	1	6.52	3.26	2.00	0.47	18.7	9.3	0.83	.163	1.86	4.19
17	Alejandro Pena A. Pena	2.03	23	4	3	.571	0	28	0	0	4	31.0	23	7	7	2	14	1	10	6	128	5	8.13	4.06	2.00	0.58	21.9	10.9	1.19	.253	2.03	6.68
18	Pedro Borbon P. Borbon	2.08	20	1	1	.500	0	10	0	0	3	26.0	19	6	7	0	5	1	8	1	100	0	3.46	1.73	2.00	0.00	10.0	5.0	0.92	.226	2.42	6.58
19	Mike Stanton M. Stanton	2.10	53	5	2	.714	0	47	0	0	1	55.2	43	13	15	1	21	0	15	9	222	2	7.60	3.40	2.24	0.16	21.2	9.5	1.15	.275	2.43	6.95
20	Brad Lidge B. Lidge	2.18	39	2	4	.333	0	62	0	0	18	45.1	32	11	11	2	19	3	32	2	185	3	12.31	3.77	3.26	0.40	33.5	10.3	1.13	.303	2.18	6.35
21	Kenley Jansen K. Jansen	2.20	59	3	2	.600	0	94	0	0	20	65.1	34	16	18	7	18	3	47	3	250	0	12.95	2.48	5.22	0.96	37.6	7.2	0.80	.211	2.48	4.68
22	Tug McGraw T. McGraw	2.24	26	3	3	.500	0	48	0	0	8	52.1	38	13	15	1	33	1	19	9	223	3	8.25	5.68	1.45	0.17	21.5	14.8	1.36	.264	2.58	6.54
23	Robb Nen R. Nen	2.25	20	1	0	1.000	0	20	0	0	11	20.0	20	5	7	0	8	0	17	1	88	2	9.00	3.60	2.50	0.00	22.7	9.1	1.40	.333	3.15	9.00
24	Aroldis Chapman A. Chapman	2.26	46	3	4	.429	0	73	0	0	11	51.2	39	13	16	4	21	3	29	1	213	3	12.72	3.66	3.48	0.70	34.3	9.9	1.16	.313	2.79	6.79
25	Mark Wohlers M. Wohlers	2.35	39	1	2	.333	0	44	0	0	9	38.1	33	10	12	5	17	0	25	6	164	2	10.33	3.99	2.59	1.17	26.8	10.4	1.30	.286	2.82	7.75