most innings pitched in a game by a relief pitcher

Zip Zabel has pitched the most innings by a relief pitcher in a game, with 18.1 innings versus the Brooklyn Robins on June 17, 1915.

Interpreted as:

most innings pitched in a regular-season game by a relief pitcher

	NAME	IP	DATE	TM		OPP	DEC	GS	ERA	SO	CG	SHO	SV	H	ER	R	HR	BB	HBP	GF	IBB	TBF	WP
1	Zip Zabel Z. Zabel	18.1	6/17/1915	CHC	vs	BKN	W	0	0.98	6	0	0	0	9	2	2	0	1	0	1		78	0
2	Eddie Rommel E. Rommel	17.0	7/10/1932	PHA	@	CLE	W	0	6.88	7	0	0	0	29	13	14	0	9	0	1		87	2
3	Elmer Jacobs E. Jacobs	16.2	8/22/1917	PIT	@	BKN	L	0	0.54	1	0	0	0	17	1	1	0	3	0	1		66	0
4	Clarence Currie C. Currie	16.0	8/17/1902	SLN	vs	BKN		0	1.13	1	0	0	0	13	2	2	0	5	1	1			0
5	Tom Sheehan T. Sheehan	15.2	8/18/1924	CIN	vs	NYG	W	0	1.15	8	0	0	0	11	2	3	0	7	0	1		63	0
6	Carl Weilman C. Weilman	14.2	7/25/1913	SLA	@	WSH		0	2.45	6	0	0	0	11	4	6	0	2	1	1		56	0
7	Leon Cadore L. Cadore	14.1	5/30/1921	BKN	@	BSN	L	0	1.88	6	0	0	0	9	3	3	0	3	1	1		56	0
8	Jack Warhop J. Warhop	14.1	7/5/1912	NYH	@	WSH	L	0		9	0	0	0	12		4	0	7	0	1		60	0
9	Bob Osborn B. Osborn	14.0	5/17/1927	CHC	@	BSN	W	0	0.00	1	0	0	0	6	0	0	0	2	0	1		50	0
10	Roy Moore R. Moore	14.0	8/31/1920	PHA	vs	DET		0	1.93	4	0	0	0	13	3	3	0	3	0	1		52	1
11	Lindy McDaniel L. McDaniel	13.0	8/4/1973	NYY	@	DET	W	0	0.69	3	0	0	0	6	1	1	1	3	0	1	1	48	0
12	Larry Cheney L. Cheney	13.0	8/22/1917	BKN	vs	PIT		0	0.00	7	0	0	0	9	0	0	0	1	0	0		47	0
13	Marc Hall M. Hall	13.0	7/5/1914	DET	vs	SLA	L	0	2.08	4	0	0	0	13	3	3	0	2	0	1		48	0
14	Doc Crandall D. Crandall	13.0	9/19/1909	NYG	@	CHC		0		8	0	0	0	8		2	0	2	1	1		44	1
15	Joe Sullivan J. Sullivan	12.2	5/10/1936	DET	vs	CLE	L	0	2.13	2	0	0	0	9	3	4	0	3	0	0		51	2
16	Bud Tinning B. Tinning	12.2	8/17/1932	CHC	vs	BSN		0	0.00	4	0	0	0	7	0	0	0	3	0	0		45	0
17	Carl Hubbell C. Hubbell	12.2	8/5/1928	NYG	vs	SLN	L	0	1.42	2	0	0	0	7	2	2	0	4	0	1		46	0
18	Walter Johnson W. Johnson	12.2	7/5/1912	WSH	vs	NYH	W	0		5	0	0	0	4		2	0	3	1	1		47	0
19	Cy Morgan C. Morgan	12.2	6/15/1910	PHA	@	CWS	L	0		8	0	0	0	10		4	0	5	2	1		49	0
20	Dick Errickson D. Errickson	12.0	5/5/1939	BSN	vs	CIN	L	0	2.25	4	0	0	0	6	3	3	0	5	0	1		47	0
21	Whitey Wilshere W. Wilshere	12.0	7/27/1935	PHA	vs	BSA		0	1.50	7	0	0	0	7	2	2	1	5	1	0		48	0
22	Syl Johnson S. Johnson	12.0	8/28/1930	SLN	@	CHC	W	0	1.50	9	0	0	0	9	2	2	0	1	0	1		44	0
23	Ted Blankenship T. Blankenship	12.0	7/3/1922	CWS	vs	DET	L	0	1.50	2	0	0	0	9	2	2	0	5	0	1		48	0
24	George Mogridge G. Mogridge	12.0	5/24/1918	NYY	vs	CLE	L	0	0.75	2	0	0	0	8	1	1	1	2	0	1		45	0
25	Jock Menefee J. Menefee	12.0	7/13/1903	CHC	vs	BKN	L	0		3	0	0	0	11		4	0	6	0	1		50	1