Kevin Gausman has lost the most career games by an active pitcher, with 113 games.

Interpreted as:

current pitcher with most regular-season losses

	NAME	L	W	L%	G	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	ERA-	FIP	FIP-	H/9	PRAA
1	Kevin Gausman K. Gausman	113	112	.502	361	.498	322	3.81	1,954	4	2	0	1911.0	1,835	810	866	233	535	38	11	11	7,986	64	9.20	2.52	3.65	1.10	24.5	6.7	1.24	.307	4.08	92	3.59	85	8.64	132.7
2	Jose Quintana J. Quintana	110	113	.493	383	.507	357	3.76	1,816	2	2	0	2101.1	2,043	877	949	219	641	58	7	23	8,812	75	7.78	2.75	2.83	0.94	20.6	7.3	1.28	.300	4.06	91	3.76	90	8.75	91.5
3	Sonny Gray S. Gray	102	125	.449	339	.551	330	3.58	1,925	7	5	0	1918.0	1,675	763	836	192	621	57	2	5	7,952	106	9.03	2.91	3.10	0.90	24.2	7.8	1.20	.288	3.92	87	3.51	85	7.86	136.2
4	Yu Darvish Y. Darvish	93	115	.447	297	.553	297	3.65	2,075	2	1	0	1778.0	1,460	721	756	231	563	83	0	8	7,305	83	10.50	2.85	3.69	1.17	28.4	7.7	1.14	.282	3.83	87	3.58	85	7.39	120
5	Martín Pérez M. Pérez	93	91	.505	325	.495	279	4.41	1,153	4	3	0	1631.2	1,750	800	883	191	590	52	14	11	7,070	43	6.36	3.25	1.95	1.05	16.3	8.3	1.43	.307	4.87	100	4.44	103	9.65	-24.3
6	Kyle Freeland K. Freeland	90	64	.584	236	.416	231	4.54	944	0	0	0	1260.1	1,394	636	690	180	392	47	0	12	5,466	17	6.74	2.80	2.41	1.29	17.3	7.2	1.42	.311	4.93	94	4.57	103	9.95	-17.5
7	Aaron Nola A. Nola	89	109	.449	285	.551	285	3.83	1,876	6	4	0	1715.2	1,522	730	769	217	449	56	0	16	7,039	18	9.84	2.36	4.18	1.14	26.7	6.4	1.15	.294	4.03	91	3.50	82	7.98	147.1
8	Chris Sale C. Sale	88	145	.378	393	.622	312	3.01	2,579	16	3	12	2084.0	1,692	697	750	213	487	130	25	15	8,389	48	11.14	2.10	5.30	0.92	30.7	5.8	1.05	.297	3.24	70	2.87	68	7.31	303.3
9	Luis Castillo L. Castillo	84	83	.503	243	.497	243	3.55	1,493	1	0	0	1410.2	1,208	557	608	174	453	48	0	8	5,824	19	9.53	2.89	3.30	1.11	25.6	7.8	1.18	.283	3.88	86	3.72	88	7.71	78.1
10	Nathan Eovaldi N. Eovaldi	84	102	.452	316	.548	297	3.89	1,487	5	3	0	1702.1	1,661	736	780	188	466	55	5	17	7,124	54	7.86	2.46	3.19	0.99	20.9	6.5	1.25	.299	4.12	95	3.75	92	8.78	66.2
11	José Berríos J. Berríos	82	108	.432	275	.568	273	4.08	1,481	5	1	0	1571.2	1,474	713	765	219	473	98	0	7	6,607	35	8.48	2.71	3.13	1.25	22.4	7.2	1.24	.289	4.38	97	4.18	99	8.44	14.3
12	Robbie Ray R. Ray	81	88	.479	265	.521	261	3.94	1,734	2	1	0	1441.0	1,250	631	674	216	608	51	1	19	6,097	60	10.83	3.80	2.85	1.35	28.4	10.0	1.29	.296	4.21	94	4.06	99	7.81	5.1
13	Gerrit Cole G. Cole	80	153	.343	317	.657	317	3.18	2,251	8	5	0	1954.0	1,627	690	740	217	500	61	0	8	7,861	58	10.37	2.30	4.50	1.00	28.6	6.4	1.09	.292	3.41	79	3.16	77	7.49	213.5
14	Matthew Boyd M. Boyd	77	60	.562	213	.438	199	4.57	1,045	2	1	0	1088.0	1,053	553	589	176	336	53	2	7	4,614	32	8.64	2.78	3.11	1.46	22.6	7.3	1.28	.292	4.87	106	4.42	103	8.71	-14.8
15	Nick Pivetta N. Pivetta	76	69	.524	254	.476	209	4.47	1,329	2	0	3	1211.0	1,107	602	631	197	427	34	13	7	5,107	53	9.88	3.17	3.11	1.46	26.0	8.4	1.27	.292	4.69	105	4.22	100	8.23	1.1
16	Michael Wacha M. Wacha	75	110	.405	309	.595	288	3.89	1,416	2	2	0	1627.1	1,571	703	746	194	503	42	4	18	6,846	43	7.83	2.78	2.82	1.07	20.7	7.3	1.27	.294	4.13	96	3.96	97	8.69	17.3
17	Zack Wheeler Z. Wheeler	75	113	.399	283	.601	283	3.28	1,820	5	3	0	1728.1	1,475	630	683	166	490	76	0	14	7,086	41	9.48	2.55	3.71	0.86	25.7	6.9	1.14	.289	3.56	82	3.28	80	7.68	164.6
18	Carlos Rodón C. Rodón	72	93	.436	231	.564	226	3.73	1,409	3	1	0	1282.0	1,085	532	574	159	477	65	1	5	5,378	65	9.89	3.35	2.95	1.12	26.2	8.9	1.22	.283	4.03	90	3.83	90	7.62	58.2
19	Taijuan Walker T. Walker	71	77	.480	251	.520	230	4.18	1,088	3	1	1	1278.0	1,211	594	654	186	434	58	7	13	5,423	27	7.66	3.06	2.51	1.31	20.1	8.0	1.29	.280	4.61	102	4.50	108	8.53	-46.3
20	Sandy Alcantara S. Alcantara	67	52	.563	177	.437	169	3.65	931	12	4	0	1075.1	934	436	485	113	330	44	3	8	4,425	26	7.79	2.76	2.82	0.95	21.0	7.5	1.18	.273	4.06	86	3.85	92	7.82	37.7
21	Lucas Giolito L. Giolito	66	70	.485	206	.515	204	4.30	1,198	5	3	0	1158.2	1,017	554	593	183	441	41	1	7	4,873	49	9.31	3.43	2.72	1.42	24.6	9.0	1.26	.277	4.61	101	4.40	101	7.90	-3.7
22	Sean Manaea S. Manaea	66	79	.455	243	.545	210	4.08	1,184	3	3	0	1245.0	1,150	565	611	171	347	61	5	4	5,196	36	8.56	2.51	3.41	1.24	22.8	6.7	1.20	.285	4.42	100	4.02	98	8.31	14.6
23	Eduardo Rodriguez E. Rodriguez	66	94	.413	241	.588	235	4.19	1,297	0	0	0	1304.2	1,280	607	641	167	455	32	1	9	5,579	17	8.95	3.14	2.85	1.15	23.2	8.2	1.33	.307	4.42	95	3.96	95	8.83	34.8
24	Mitch Keller M. Keller	65	42	.607	165	.393	163	4.51	837	2	1	0	878.0	914	440	472	103	299	58	0	2	3,818	19	8.58	3.06	2.80	1.06	21.9	7.8	1.38	.322	4.84	105	4.01	96	9.37	17.2
25	Trevor Williams T. Williams	65	53	.551	219	.449	178	4.46	825	1	1	1	1009.0	1,065	500	543	146	323	38	10	12	4,361	11	7.36	2.88	2.55	1.30	18.9	7.4	1.38	.303	4.84	106	4.49	105	9.50	-27.7