Gabe Speier appeared in the most games for the Mariners in 2025, with 76 games.

	NAME	G	SEASON	TM	W	L	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	Gabe Speier G. Speier	76	2025	SEA	4	3	.571	0	2.61	82	0	0	0	62.0	43	18	19	5	11	5	4	1	243	1	11.90	1.60	7.45	0.73	33.7	4.5	0.87	.271	2.76	68	2.31	58	6.24	12.1
2	Eduard Bazardo E. Bazardo	73	2025	SEA	5	0	1.000	0	2.52	82	0	0	0	78.2	53	22	23	9	27	2	18	2	313	2	9.38	3.09	3.04	1.03	26.2	8.6	1.02	.228	2.63	66	3.64	91	6.06	3.2
3	Carlos Vargas C. Vargas	70	2025	SEA	5	5	.500	0	3.97	54	0	0	1	77.0	81	34	39	10	23	7	10	4	331	5	6.31	2.69	2.35	1.17	16.3	6.9	1.35	.300	4.56	103	4.58	114	9.47	-5.3
4	Andrés Muñoz A. Muñoz	64	2025	SEA	3	3	.500	0	1.73	83	0	0	38	62.1	36	12	18	2	28	4	47	3	254	7	11.98	4.04	2.96	0.29	32.7	11.0	1.03	.248	2.60	45	2.42	60	5.20	11.3
5	Matt Brash M. Brash	53	2025	SEA	1	3	.250	0	2.47	58	0	0	4	47.1	41	13	15	4	18	2	8	2	199	0	11.03	3.42	3.22	0.76	29.1	9.0	1.25	.316	2.85	64	3.04	76	7.80	5.2
6	Casey Legumina C. Legumina	48	2025	SEA	4	6	.400	1	5.62	55	0	0	0	49.2	47	31	36	7	25	2	17	2	219	1	9.97	4.53	2.20	1.27	25.1	11.4	1.45	.308	6.52	146	4.38	109	8.52	-2.2
7	Trent Thornton T. Thornton	33	2025	SEA	2	0	1.000	0	4.68	32	0	0	0	42.1	41	22	23	6	14	4	7	2	180	1	6.80	2.98	2.29	1.28	17.8	7.8	1.30	.282	4.89	122	4.73	118	8.72	-3.6
8	Luis Castillo L. Castillo	32	2025	SEA	11	8	.579	32	3.54	162	0	0	0	180.2	168	71	76	23	46	7	0	0	745	3	8.07	2.29	3.52	1.15	21.7	6.2	1.18	.286	3.79	92	3.87	97	8.37	2.5
9	Bryan Woo B. Woo	30	2025	SEA	15	7	.682	30	2.94	198	0	0	0	186.2	137	61	64	26	36	4	0	0	731	3	9.55	1.74	5.50	1.25	27.1	4.9	0.93	.238	3.09	77	3.46	86	6.61	11.4
10	Caleb Ferguson C. Ferguson	25	2025	SEA	3	2	.600	0	3.27	17	0	0	0	22.0	21	8	9	1	8	1	2	1	94	1	6.95	3.27	2.13	0.41	18.1	8.5	1.32	.299	3.68	85	3.40	85	8.59	1.5
11	Logan Gilbert L. Gilbert	25	2025	SEA	6	6	.500	25	3.44	173	0	0	0	131.0	104	50	53	20	31	7	0	0	535	10	11.89	2.13	5.58	1.37	32.3	5.8	1.03	.276	3.64	89	3.34	83	7.15	9.8
12	Collin Snider C. Snider	24	2025	SEA	2	1	.667	0	5.47	24	0	0	0	26.1	32	16	20	3	6	2	4	1	119	1	8.20	2.05	4.00	1.03	20.2	5.0	1.44	.345	6.84	142	3.70	92	10.94	0.9
13	George Kirby G. Kirby	23	2025	SEA	10	8	.556	23	4.21	137	0	0	0	126.0	121	59	60	15	29	7	0	0	524	3	9.79	2.07	4.72	1.07	26.1	5.5	1.19	.315	4.29	110	3.36	84	8.64	9.2
14	Emerson Hancock E. Hancock	22	2025	SEA	4	5	.444	16	4.90	64	0	0	0	90.0	93	49	51	15	31	5	2	0	385	2	6.40	3.10	2.06	1.50	16.6	8.1	1.38	.289	5.10	128	5.07	127	9.30	-11.3
15	Bryce Miller B. Miller	18	2025	SEA	4	6	.400	18	5.68	74	0	0	0	90.1	93	57	57	17	34	3	0	0	392	2	7.37	3.39	2.18	1.69	18.9	8.7	1.41	.288	5.68	148	5.16	129	9.27	-12.3
16	Logan Evans L. Evans	16	2025	SEA	6	5	.545	15	4.32	59	0	0	0	81.1	82	39	45	13	31	4	0	1	350	5	6.53	3.43	1.90	1.44	16.9	8.9	1.39	.284	4.98	112	5.05	126	9.07	-9.9
17	Jackson Kowar J. Kowar	15	2025	SEA	2	0	1.000	0	4.24	15	0	0	0	17.0	14	8	8	4	7	1	9	0	71	2	7.94	3.71	2.14	2.12	21.1	9.9	1.24	.227	4.24	110	5.83	146	7.41	-3.6
18	Luke Jackson L. Jackson	10	2025	SEA	0	0		0	2.38	10	0	0	0	11.1	6	3	6	0	4	1	5	1	45	0	7.94	3.18	2.50	0.00	22.2	8.9	0.88	.200	4.76	62	2.69	67	4.76	1.7
19	Tayler Saucedo T. Saucedo	10	2025	SEA	0	0		0	7.43	12	0	0	0	13.1	19	11	12	2	6	1	5	0	66	0	8.10	4.05	2.00	1.35	18.2	9.1	1.88	.378	8.10	193	4.85	121	12.83	-1.3
20	Gregory Santos G. Santos	8	2025	SEA	1	1	.500	0	5.14	0	0	0	0	7.0	8	4	6	0	8	0	2	2	36	2	0.00	10.29	0.00	0.00	0.0	22.2	2.29	.286	7.71	134	6.56	164	10.29	-2.1
21	Troy Taylor T. Taylor	8	2025	SEA	0	0		0	12.15	2	0	0	0	6.2	14	9	9	2	3	1	4	0	37	0	2.70	4.05	0.67	2.70	5.4	8.1	2.55	.414	12.15	316	8.23	205	18.90	-3.3
22	Casey Lawrence C. Lawrence	5	2025	SEA	1	2	.333	0	3.00	6	0	0	0	15.0	20	5	12	2	1	0	3	0	65	1	3.60	0.60	6.00	1.20	9.2	1.5	1.40	.321	7.20	78	4.26	106	12.00	-0.5
23	Zach Pop Z. Pop	4	2025	SEA	0	0		0	13.50	3	0	0	0	5.1	10	8	9	3	2	1	1	0	30	0	5.06	3.38	1.50	5.06	10.0	6.7	2.25	.333	15.19	351	11.00	275	16.88	-4.3
24	Juan Burgos J. Burgos	4	2025	SEA	0	0		0	4.05	8	0	0	0	6.2	7	3	3	0	2	1	4	0	30	0	10.80	2.70	4.00	0.00	26.7	6.7	1.35	.368	4.05	105	2.08	52	9.45	1.5
25	José Castillo J. Castillo	3	2025	SEA	1	0	1.000	0	0.00	1	0	0	0	3.0	3	0	1	0	2	0	1	1	13	0	3.00	6.00	0.50	0.00	7.7	15.4	1.67	.300	3.00	0	4.46	111	9.00	-0.2