Joe Harris has pitched the most innings in a loss, with 24 innings against the Philadelphia Athletics on September 1, 1906.

Interpreted as:

most ip in a regular-season loss by pitcher

	NAME	IP	L	DATE	TM		OPP	DEC	W	L%	GS	ERA	SO	CG	SHO	SV	H	ER	R	HR	BB	HBP	GF	IBB	TBF	WP
1	Joe Harris J. Harris	24.0	1	9/1/1906	BSA	vs	PHA	L	0	1.000	1		14	1	0	0	16		4	0	2	1	0		87	0
2	Bob Smith B. Smith	22.0	1	5/17/1927	BSN	vs	CHC	L	0	1.000	1	1.23	5	1	0	0	20	3	4	0	9	0	0		89	0
3	Ted Lyons T. Lyons	21.0	1	5/24/1929	CWS	vs	DET	L	0	1.000	1	2.57	4	1	0	0	24	6	6	0	2	0	0		85	0
4	Art Nehf A. Nehf	21.0	1	8/1/1918	BSN	vs	PIT	L	0	1.000	1	0.86	8	1	0	0	12	2	2	0	5	0	0		77	0
5	Babe Adams B. Adams	21.0	1	7/17/1914	PTN	vs	NYG	L	0	1.000	1	1.29	6	1	0	0	12	3	3	1	0	0	0		75	0
6	Milt Watson M. Watson	20.0	1	7/17/1918	PHN	@	CHC	L	0	1.000	1	0.90	5	1	0	0	19	2	2	0	4	1	0		82	0
7	Tully Sparks T. Sparks	20.0	1	8/24/1905	PHN	vs	CHC	L	0	1.000	1		6	1	0	0	19		2	0	1	3	0		72	0
8	Cy Young C. Young	20.0	1	7/4/1905	BSA	vs	PHA	L	0	1.000	1		9	1	0	0	12		4	1	0	1	0		75	0
9	Eddie Plank E. Plank	19.0	1	9/27/1912	PHA	vs	WSH	L	0	1.000	1		5	1	0	0	13		5	0	6	1	0		75	1
10	Otto Hess O. Hess	19.0	1	7/31/1912	BSN	vs	PIT	L	0	1.000	1	2.37	4	1	0	0	15	5	7	0	8	0	0		77	0
11	Jeff Pfeffer J. Pfeffer	18.2	1	6/17/1915	BKN	@	CHC	L	0	1.000	1	0.96	6	1	0	0	13	2	4	1	8	0	0		78	0
12	Deacon Phillippe D. Phillippe	18.2	1	6/22/1902	PIT	@	CHO	L	0	1.000	1	0.96	6	1	0	0	14	2	3	0	3	0	0		70	0
13	Sherry Smith S. Smith	18.1	1	5/3/1920	BKN	@	BSN	L	0	1.000	1	0.98	3	1	0	0	13	2	2	0	5	0	0		69	0
14	Jeff Pfeffer J. Pfeffer	18.0	1	6/1/1919	BKN	vs	PHN	L	0	1.000	1	3.50	6	1	0	0	23	7	10	1	3	0	0		77	0
15	Jack Taylor J. Taylor	18.0	1	6/24/1905	SLN	vs	CHC	L	0	1.000	1		7	1	0	0	11		2	0	4	0	0		68	0
16	Charlie Robertson C. Robertson	17.1	1	5/14/1927	BSN	vs	CHC	L	0	1.000	1	3.12	4	0	0	0	13	6	6	0	4	0	0		66	1
17	Walter Johnson W. Johnson	17.1	1	8/4/1918	WSH	@	DET	L	0	1.000	1	3.12	5	1	0	0	16	6	7	0	8	0	0		75	0
18	Lefty Williams L. Williams	17.1	1	5/15/1918	CWS	@	WSH	L	0	1.000	1	0.52	3	1	0	0	8	1	1	0	2	1	0		63	1
19	Saul Rogovin S. Rogovin	17.0	1	7/12/1951	CWS	vs	BSA	L	0	1.000	1	2.12	9	1	0	0	10	4	5	1	6	0	0	0	63	0
20	Ray Fisher R. Fisher	17.0	1	8/27/1920	CIN	vs	NYG	L	0	1.000	1	3.18	4	1	0	0	18	6	6	0	5	0	0		71	0
21	George McConnell G. McConnell	17.0	1	6/28/1916	CHC	vs	PIT	L	0	1.000	1	1.59	7	0	0	0	12	3	3	2	3	0	0		64	0
22	Oscar Jones O. Jones	17.0	1	8/11/1904	BKN	vs	SLN	L	0	1.000	1		6	1	0	0	10		4	0	2	0	0		59	0
23	Bill Dinneen B. Dinneen	17.0	1	7/9/1902	BSA	vs	PHA	L	0	1.000	1	2.12	5	1	0	0	11	4	4	1	5	0	0		65	0
24	Elmer Jacobs E. Jacobs	16.2	1	8/22/1917	PIT	@	BKN	L	0	1.000	0	0.54	1	0	0	0	17	1	1	0	3	0	1		66	0
25	Jim Pastorius J. Pastorius	16.2	1	8/22/1908	BKN	@	PIT	L	0	1.000	1		2	1	0	0	11		1	0	8	0	0		66	0