most losses by pitcher in single season before all-star break

Denny McLain has lost the most games in a season before the All-Star Game, with 15 games in 1971.

	NAME	L	SEASON	TM	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	H/9
1	Denny McLain D. McLain	15	1971	WSH	5	.750	21	.250	21	4.47	78	7	2	0	141.0	154	70	79	23	47	2	0	8	607	3	4.98	3.00	1.66	1.47	12.9	7.7	1.43	.287	5.04	9.83
2	Bill Wegman B. Wegman	14	1993	MIL	4	.778	18	.222	18	4.34	49	5	0	0	118.1	132	57	67	13	33	2	0	5	503	0	3.73	2.51	1.48	0.99	9.7	6.6	1.39	.293	5.10	10.04
3	Gaylord Perry G. Perry	14	1975	TOT	7	.667	22	.333	22	4.33	114	12	2	0	170.1	185	82	95	20	50	2	0	6	736	4	6.02	2.64	2.28	1.06	15.5	6.8	1.38	.300	5.02	9.77
4	Gaylord Perry G. Perry	14	1973	CLE	8	.636	25	.364	25	3.59	150	17	2	0	210.2	205	84	95	22	67	4	0	6	872	14	6.41	2.86	2.24	0.94	17.2	7.7	1.29	.291	4.06	8.76
5	Wilbur Wood W. Wood	14	1973	CWS	18	.438	32	.563	31	2.98	142	17	4	0	247.2	233	82	102	17	56	2	1	2	1,022	5	5.16	2.03	2.54	0.62	13.9	5.5	1.17	.268	3.71	8.47
6	Jeremy Bonderman J. Bonderman	13	2003	DET	3	.813	18	.188	18	4.88	78	0	0	0	103.1	114	56	65	10	31	3	0	2	450	9	6.79	2.70	2.52	0.87	17.3	6.9	1.40	.317	5.66	9.93
7	Mike Maroth M. Maroth	13	2003	DET	4	.765	19	.235	19	4.89	52	1	0	0	112.1	119	61	65	14	27	5	0	2	479	6	4.17	2.16	1.93	1.12	10.9	5.6	1.30	.276	5.21	9.53
8	Jose Lima J. Lima	13	2000	HOU	2	.867	18	.133	18	7.36	78	0	0	0	106.1	145	87	93	29	37	1	0	2	496	2	6.60	3.13	2.11	2.45	15.7	7.5	1.71	.330	7.87	12.27
9	Jose DeLeon J. DeLeon	13	1985	PIT	2	.867	19	.133	19	4.72	114	0	0	0	118.1	98	62	65	10	65	1	0	1	509	5	8.67	4.94	1.75	0.76	22.4	12.8	1.38	.276	4.94	7.45
10	Wilbur Wood W. Wood	13	1975	CWS	7	.650	24	.350	24	4.38	69	8	1	0	158.1	190	77	87	15	46	4	0	4	690	6	3.92	2.61	1.50	0.85	10.0	6.7	1.49	.315	4.95	10.80
11	Randy Jones R. Jones	13	1974	SDP	7	.650	24	.350	22	4.07	84	3	1	1	135.0	142	61	67	8	45	4	2	3	582	1	5.60	3.00	1.87	0.53	14.4	7.7	1.39	.304	4.47	9.47
12	Frank Tanana F. Tanana	13	1974	CAL	6	.684	24	.316	20	3.83	81	4	0	0	150.1	157	64	70	20	50	5	2	2	645	3	4.85	2.99	1.62	1.20	12.6	7.8	1.38	.280	4.19	9.40
13	Clyde Wright C. Wright	13	1973	CAL	8	.619	24	.381	24	3.28	48	10	1	0	167.1	173	61	71	13	56	0	0	0	714	3	2.58	3.01	0.86	0.70	6.7	7.8	1.37	.268	3.82	9.30
14	Sammy Ellis S. Ellis	13	1966	CIN	5	.722	20	.278	18	5.17	76	5	0	0	115.0	105	66	69	20	38	2	1	4	484	2	5.95	2.97	2.00	1.57	15.7	7.9	1.24	.244	5.40	8.22
15	Roger Craig R. Craig	13	1963	NYM	2	.867	22	.133	17	3.79	72	7	0	2	130.2	140	55	66	12	37	3	4	0	569	3	4.96	2.55	1.95	0.83	12.7	6.5	1.35	.288	4.55	9.64
16	Dick Ellsworth D. Ellsworth	13	1962	CHC	4	.765	22	.235	18	6.07	61	2	0	1	112.2	137	76	84	17	45	3	3	2	506	12	4.87	3.59	1.36	1.36	12.1	8.9	1.62	.316	6.71	10.94
17	Bob Porterfield B. Porterfield	13	1955	WSH	7	.650	22	.350	19	4.63	58	6	1	0	126.1	133	65	77	11	40	1	2	4	540	0	4.13	2.85	1.45	0.78	10.7	7.4	1.37	.284	5.49	9.47
18	Murry Dickson M. Dickson	13	1952	PIT	5	.722	19	.278	19	3.71	47	9	1	0	136.0	139	56	73	13	51	0	0		588	0	3.11	3.38	0.92	0.86	8.0	8.7	1.40	.264	4.83	9.20
19	Lou Brissie L. Brissie	13	1950	PHA	3	.813	25	.188	16	4.14	53	9	1	6	130.1	121	60	68	13	61	4	9		566	4	3.66	4.21	0.87	0.90	9.4	10.8	1.40	.248	4.70	8.36
20	Eddie Smith E. Smith	13	1942	CWS	2	.867	16	.133	16	3.72	47	10	0	0	123.1	123	51	61	13	58	1	0		542	4	3.43	4.23	0.81	0.95	8.7	10.7	1.47	.260	4.45	8.98
21	George Caster G. Caster	13	1940	PHA	2	.867	18	.133	13	5.88	44	5	0	0	98.0	128	64	84	7	38	2	3		461	3	4.04	3.49	1.16	0.64	9.5	8.2	1.69	.327	7.71	11.76
22	Dakota Hudson D. Hudson	12	2024	COL	2	.857	17	.143	17	5.84	48	0	0	0	86.1	96	56	61	10	46	5	0	0	391	3	5.00	4.80	1.04	1.04	12.3	11.8	1.64	.305	6.36	10.01
23	Joan Adon J. Adon	12	2022	WSH	1	.923	14	.077	14	7.10	55	0	0	0	64.2	76	51	53	8	39	6	0	1	310	7	7.65	5.43	1.41	1.11	17.7	12.6	1.78	.337	7.38	10.58
24	Patrick Corbin P. Corbin	12	2022	WSH	4	.750	19	.250	19	5.87	91	1	0	0	99.2	134	65	76	17	35	3	0	1	468	2	8.22	3.16	2.60	1.54	19.4	7.5	1.70	.363	6.86	12.10
25	Jorge López J. López	12	2021	BAL	2	.857	18	.143	18	5.95	81	0	0	0	84.2	100	56	57	14	38	6	0	2	385	5	8.61	4.04	2.13	1.49	21.0	9.9	1.63	.350	6.06	10.63