Mason Miller had the highest K/9 with 50.0+ innings pitched this season, with 15.18 per nine innings.

Interpreted as:

highest k/9 MLB pitchers min 50 innings this regular season

	NAME	K/9	IP	SEASON	TM	G	W	L	W%	GS	ERA	SO	CG	SHO	SV	H	ER	R	HR	BB	HBP	GF	IBB	TBF	WP	BB/9	K/BB	HR/9	K%	BB%	WHIP	BABIP	RA	ERA-	FIP	FIP-	H/9	PRAA
1	Mason Miller M. Miller	15.18	61.2	2025	TOT	60	1	2	.333	0	2.63	104	0	0	22	28	18	19	5	28	1	37	2	234	3	4.09	3.71	0.73	44.4	12.0	0.91	.240	2.77	64	2.22	53	4.09	13.2
2	Cole Ragans C. Ragans	14.30	61.2	2025	KCR	13	3	3	.500	13	4.67	98	0	0	0	53	32	33	7	20	2	0	0	257	3	2.92	4.90	1.02	38.1	7.8	1.18	.354	4.82	109	2.50	60	7.74	11.5
3	Griffin Jax G. Jax	13.50	66.0	2025	TOT	73	1	7	.125	2	4.23	99	0	0	0	64	31	33	7	21	1	6	3	283	0	2.86	4.71	0.95	35.0	7.4	1.29	.368	4.50	105	2.51	61	8.73	11.9
4	Jeremiah Estrada J. Estrada	13.32	73.0	2025	SDP	77	4	5	.444	0	3.45	108	0	0	3	58	28	31	12	27	3	7	2	304	3	3.33	4.00	1.48	35.5	8.9	1.16	.299	3.82	85	3.54	87	7.15	4.5
5	Bryan Abreu B. Abreu	13.31	71.0	2025	HOU	70	3	4	.429	0	2.28	105	0	0	7	51	18	18	4	31	4	19	0	296	4	3.93	3.39	0.51	35.5	10.5	1.15	.309	2.28	56	2.38	58	6.46	13.9
6	Edwin Díaz E. Díaz	13.30	66.1	2025	NYM	62	6	3	.667	0	1.63	98	0	0	28	37	12	14	4	21	8	48	0	258	7	2.85	4.67	0.54	38.0	8.1	0.87	.260	1.90	40	2.27	55	5.02	13.5
7	Devin Williams D. Williams	13.06	62.0	2025	NYY	67	4	6	.400	0	4.79	90	0	0	18	45	33	37	5	25	4	29	1	259	4	3.63	3.60	0.73	34.7	9.7	1.13	.296	5.37	117	2.68	62	6.53	10.9
8	Josh Hader J. Hader	12.99	52.2	2025	HOU	48	6	2	.750	0	2.05	76	0	0	28	29	12	16	8	16	2	41	1	206	2	2.73	4.75	1.37	36.9	7.8	0.85	.202	2.73	51	3.24	79	4.96	5.2
9	Cade Smith C. Smith	12.71	73.2	2025	CLE	76	8	5	.615	0	2.93	104	0	0	16	55	24	31	4	19	4	30	3	300	3	2.32	5.47	0.49	34.7	6.3	1.00	.302	3.79	72	1.95	47	6.72	18
10	Aroldis Chapman A. Chapman	12.47	61.1	2025	BOS	67	5	3	.625	0	1.17	85	0	0	32	28	8	9	3	15	0	43	0	228	6	2.20	5.67	0.44	37.3	6.6	0.70	.200	1.32	27	1.73	41	4.11	16.8
11	David Bednar D. Bednar	12.35	62.2	2025	TOT	64	6	5	.545	0	2.30	86	0	0	27	46	16	18	4	19	1	51	2	251	4	2.73	4.53	0.57	34.3	7.6	1.04	.298	2.59	54	2.17	52	6.61	14
12	Edwin Uceta E. Uceta	12.20	76.0	2025	TBR	70	10	3	.769	0	3.79	103	0	0	1	62	32	33	11	27	8	11	3	321	0	3.20	3.81	1.30	32.1	8.4	1.17	.297	3.91	97	3.68	91	7.34	3.1
13	Ronny Henriquez R. Henriquez	12.08	73.0	2025	MIA	69	7	1	.875	0	2.22	98	0	0	7	53	18	23	8	27	4	9	2	303	2	3.33	3.63	0.99	32.3	8.9	1.10	.271	2.84	52	3.14	76	6.53	8
14	Alex Vesia A. Vesia	12.07	59.2	2025	LAD	68	4	2	.667	0	3.02	80	0	0	5	37	20	21	9	22	5	11	3	237	3	3.32	3.64	1.36	33.8	9.3	0.99	.231	3.17	73	3.76	89	5.58	3
15	Garrett Cleavinger G. Cleavinger	12.03	61.1	2025	TBR	67	2	6	.250	0	2.35	82	0	0	2	40	16	17	9	18	7	9	0	243	1	2.64	4.56	1.32	33.7	7.4	0.95	.244	2.49	60	3.58	89	5.87	3.2
16	Brendon Little B. Little	11.99	68.1	2025	TOR	79	4	2	.667	0	3.03	91	0	0	1	48	23	28	2	45	2	4	4	295	7	5.93	2.02	0.26	30.8	15.3	1.36	.297	3.69	75	2.91	70	6.32	9.6
17	Andrés Muñoz A. Muñoz	11.98	62.1	2025	SEA	64	3	3	.500	0	1.73	83	0	0	38	36	12	18	2	28	4	47	3	254	7	4.04	2.96	0.29	32.7	11.0	1.03	.248	2.60	45	2.42	60	5.20	11.3
18	Gabe Speier G. Speier	11.90	62.0	2025	SEA	76	4	3	.571	0	2.61	82	0	0	0	43	18	19	5	11	5	4	1	243	1	1.60	7.45	0.73	33.7	4.5	0.87	.271	2.76	68	2.31	58	6.24	12.1
19	Randy Rodríguez R. Rodríguez	11.90	50.2	2025	SFG	50	3	5	.375	0	1.78	67	0	0	4	34	10	12	4	11	4	15	0	198	2	1.95	6.09	0.71	33.8	5.6	0.89	.268	2.13	43	2.40	60	6.04	9.1
20	Phil Maton P. Maton	11.89	61.1	2025	TOT	63	4	5	.444	0	2.79	81	0	0	5	42	19	21	3	23	7	22	2	248	1	3.38	3.52	0.44	32.7	9.3	1.06	.291	3.08	68	2.59	63	6.16	10.5
21	Logan Gilbert L. Gilbert	11.89	131.0	2025	SEA	25	6	6	.500	25	3.44	173	0	0	0	104	50	53	20	31	7	0	0	535	10	2.13	5.58	1.37	32.3	5.8	1.03	.276	3.64	89	3.34	83	7.15	9.8
22	Jacob Misiorowski J. Misiorowski	11.86	66.0	2025	MIL	15	5	3	.625	14	4.36	87	0	0	0	51	32	34	8	31	3	0	0	273	1	4.23	2.81	1.09	31.9	11.4	1.24	.299	4.64	104	3.61	87	6.95	4.1
23	Chris Sale C. Sale	11.82	125.2	2025	ATL	21	7	5	.583	20	2.58	165	0	0	0	102	36	38	11	32	11	0	0	510	3	2.29	5.16	0.79	32.4	6.3	1.07	.313	2.72	61	2.67	66	7.31	19.6
24	Zack Wheeler Z. Wheeler	11.73	149.2	2025	PHI	24	10	5	.667	24	2.71	195	1	0	0	107	45	48	19	33	8	0	0	585	2	1.98	5.91	1.14	33.3	5.6	0.94	.267	2.89	64	2.99	71	6.43	20
25	Tylor Megill T. Megill	11.72	68.1	2025	NYM	14	5	5	.500	14	3.95	89	0	0	0	60	30	37	6	33	7	0	0	305	3	4.35	2.70	0.79	29.2	10.8	1.36	.318	4.87	98	3.42	84	7.90	5.1