Grant Dayton has the worst career ERA in the postseason when pitching at least 5 innings, with an ERA of 18.56.

Interpreted as:

highest postseason era by a player, minimum 5 ip

	NAME	ERA	IP	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	Grant Dayton G. Dayton	18.56	5.1	8	0	0		0	8	0	0	0	14	11	11	4	3	1	1	0	34	0	13.50	5.06	2.67	6.75	23.5	8.8	3.19	.556	18.56	23.63
2	Bobby Ayala B. Ayala	17.47	5.2	5	0	0		0	5	0	0	0	13	11	11	3	7	0	0	1	36	0	7.94	11.12	0.71	4.76	13.9	19.4	3.53	.476	17.47	20.65
3	Chris Reitsma C. Reitsma	17.05	6.1	7	0	0		0	2	0	0	0	12	12	12	2	3	0	1	2	34	1	2.84	4.26	0.67	2.84	5.9	8.8	2.37	.370	17.05	17.05
4	Jay Witasick J. Witasick	15.58	8.2	8	0	1	.000	0	8	0	0	0	21	15	16	2	3	0	2	0	51	1	8.31	3.12	2.67	2.08	15.7	5.9	2.77	.500	16.62	21.81
5	Odalis Perez O. Perez	15.00	6.0	5	1	1	.500	2	4	0	0	0	13	10	10	4	9	0	1	1	38	0	6.00	13.50	0.44	6.00	10.5	23.7	3.67	.429	15.00	19.50
6	Shaun Marcum S. Marcum	14.90	9.2	3	0	3	.000	3	5	0	0	0	17	16	16	3	5	0	0	1	49	0	4.66	4.66	1.00	2.79	10.2	10.2	2.28	.389	14.90	15.83
7	Junior Thompson J. Thompson	14.63	8.0	2	0	2	.000	2	5	0	0	0	13	13	13	5	8	0	0	0	43	1	5.63	9.00	0.63	5.63	11.6	18.6	2.63	.320	14.63	14.62
8	Mark Lowe M. Lowe	13.50	6.0	10	0	1	.000	0	7	0	0	0	8	9	9	1	3	1	2	0	30	0	10.50	4.50	2.33	1.50	23.3	10.0	1.83	.389	13.50	12.00
9	Bob Friend B. Friend	13.50	6.0	3	0	2	.000	2	7	0	0	0	13	9	10	0	3	2	0	0	35	0	10.50	4.50	2.33	0.00	20.0	8.6	2.67	.565	15.00	19.50
10	Tommy Greene T. Greene	13.11	11.2	3	1	1	.500	3	8	0	0	0	19	17	17	3	11	0	0	0	62	0	6.17	8.49	0.73	2.31	12.9	17.7	2.57	.400	13.11	14.66
11	Dylan Cease D. Cease	12.91	7.2	4	0	1	.000	3	8	0	0	0	12	11	11	2	6	0	0	0	41	0	9.39	7.04	1.33	2.35	19.5	14.6	2.35	.400	12.91	14.09
12	Steve Reed S. Reed	12.91	7.2	12	1	0	1.000	0	5	0	0	0	12	11	11	1	4	4	1	1	43	0	5.87	4.70	1.25	1.17	11.6	9.3	2.09	.379	12.91	14.09
13	Gil Heredia G. Heredia	12.79	6.1	2	1	1	.500	2	3	0	0	0	11	9	9	0	3	1	0	0	33	0	4.26	4.26	1.00	0.00	9.1	9.1	2.21	.423	12.79	15.63
14	Cory Lidle C. Lidle	12.71	5.2	3	0	1	.000	1	1	0	0	0	11	8	10	0	3	0	0	0	31	0	1.59	4.76	0.33	0.00	3.2	9.7	2.47	.407	15.88	17.47
15	Kodai Senga K. Senga	12.60	5.0	3	0	1	.000	2	4	0	0	0	6	7	7	1	7	1	0	0	29	1	7.20	12.60	0.57	1.80	13.8	24.1	2.60	.313	12.60	10.80
16	Eric Show E. Show	12.38	8.0	3	0	2	.000	3	4	0	0	0	12	11	12	7	5	0	0	0	41	0	4.50	5.63	0.80	7.88	9.8	12.2	2.13	.200	13.50	13.50
17	Vic Lombardi V. Lombardi	12.15	6.2	2	0	1	.000	2	5	0	0	0	14	9	9	1	1	0	0	1	34	1	6.75	1.35	5.00	1.35	14.7	2.9	2.25	.481	12.15	18.90
18	Dick Coffman D. Coffman	12.00	6.0	4	0	0		0	2	0	0	0	7	8	8	1	6	0	1	1	30	0	3.00	9.00	0.33	1.50	6.7	20.0	2.17	.286	12.00	10.50
19	Ron Willis R. Willis	11.81	5.1	6	0	0		0	4	0	0	0	4	7	8	0	8	1	1	3	27	0	6.75	13.50	0.50	0.00	14.8	29.6	2.25	.286	13.50	6.75
20	Ken Giles K. Giles	11.74	7.2	7	0	2	.000	0	10	0	0	2	12	10	10	3	5	0	4	1	40	3	11.74	5.87	2.00	3.52	25.0	12.5	2.22	.409	11.74	14.09
21	Manny Delcarmen M. Delcarmen	11.42	8.2	11	1	0	1.000	0	8	0	0	0	11	11	11	2	8	2	2	0	46	0	8.31	8.31	1.00	2.08	17.4	17.4	2.19	.346	11.42	11.42
22	Jacob Webb J. Webb	11.05	7.1	8	0	0		0	12	0	0	0	11	9	9	4	4	2	1	0	39	0	14.73	4.91	3.00	4.91	30.8	10.3	2.05	.412	11.05	13.50
23	Chris Narveson C. Narveson	11.05	7.1	6	0	0		0	13	0	0	0	7	9	9	5	2	0	2	1	33	0	15.95	2.45	6.50	6.14	39.4	6.1	1.23	.154	11.05	8.59
24	Carlos Silva C. Silva	10.80	5.0	1	0	1	.000	1	1	0	0	0	10	6	6	1	0	0	0	0	24	0	1.80	0.00		1.80	4.2	0.0	2.00	.409	10.80	18.00
25	Ben Weber B. Weber	10.80	8.1	9	0	1	.000	0	8	0	0	0	15	10	10	1	4	1	3	1	43	0	8.64	4.32	2.00	1.08	18.6	9.3	2.28	.483	10.80	16.20