Corbin Burnes had the highest K/9 in 2021, with 12.61 per nine innings.

Interpreted as:

top 15% strike outs per 9 innings with a minimum of 1 IP per team game by a player 2021

	NAME	K/9	SEASON	TM	G	W	L	W%	GS	ERA	SO	CG	SHO	SV	IP	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	Corbin Burnes C. Burnes	12.61	2021	MIL	28	11	5	.688	28	2.43	234	0	0	0	167.0	123	45	47	7	34	6	0	0	657	5	1.83	6.88	0.38	35.6	5.2	0.94	.309	2.53	58	1.62	38	6.63	48.9
2	Dylan Cease D. Cease	12.28	2021	CWS	32	13	7	.650	32	3.91	226	1	1	0	165.2	139	72	77	20	68	9	0	0	708	13	3.69	3.32	1.09	31.9	9.6	1.25	.309	4.18	90	3.40	76	7.55	18.9
3	Gerrit Cole G. Cole	12.06	2021	NYY	30	16	8	.667	30	3.23	243	2	1	0	181.1	151	65	69	24	41	2	0	0	726	5	2.03	5.93	1.19	33.5	5.6	1.06	.305	3.42	76	2.91	67	7.49	28.1
4	Max Scherzer M. Scherzer	11.84	2021	TOT	30	15	4	.789	30	2.46	236	1	0	0	179.1	119	49	53	23	36	10	0	0	693	2	1.81	6.56	1.15	34.1	5.2	0.86	.247	2.66	59	2.97	69	5.97	26
5	Robbie Ray R. Ray	11.54	2021	TOR	32	13	7	.650	32	2.84	248	0	0	0	193.1	150	61	62	33	52	4	0	0	773	5	2.42	4.77	1.54	32.1	6.7	1.04	.268	2.89	63	3.68	87	6.98	11.8
6	Aaron Nola A. Nola	11.11	2021	PHI	32	9	9	.500	32	4.63	223	1	1	0	180.2	165	93	95	26	39	9	0	1	749	0	1.94	5.72	1.30	29.8	5.2	1.13	.308	4.73	110	3.36	78	8.22	19.1
7	Yu Darvish Y. Darvish	10.77	2021	SDP	30	8	11	.421	30	4.22	199	0	0	0	166.1	138	78	81	28	44	8	0	1	681	9	2.38	4.52	1.52	29.2	6.5	1.09	.274	4.38	107	3.90	93	7.47	5.6
8	Kevin Gausman K. Gausman	10.64	2021	SFG	33	14	6	.700	33	2.81	227	0	0	0	192.0	150	60	66	20	50	4	0	1	775	7	2.34	4.54	0.94	29.3	6.5	1.04	.274	3.09	70	3.00	74	7.03	23.5
9	Brandon Woodruff B. Woodruff	10.59	2021	MIL	30	9	10	.474	30	2.56	211	0	0	0	179.1	130	51	54	18	43	7	0	0	708	2	2.16	4.91	0.90	29.8	6.1	0.96	.261	2.71	61	2.95	69	6.52	26.4
10	Tyler Mahle T. Mahle	10.50	2021	CIN	33	13	6	.684	33	3.75	210	0	0	0	180.0	158	75	78	24	64	10	0	0	759	4	3.20	3.28	1.20	27.7	8.4	1.23	.297	3.90	85	3.80	85	7.90	12.9
11	Charlie Morton C. Morton	10.47	2021	ATL	33	14	6	.700	33	3.34	216	0	0	0	185.2	136	69	77	16	58	17	0	1	756	5	2.81	3.72	0.78	28.6	7.7	1.04	.267	3.73	79	3.17	75	6.59	21.4
12	Zack Wheeler Z. Wheeler	10.42	2021	PHI	32	14	10	.583	32	2.78	247	3	2	0	213.1	169	66	72	16	46	8	0	1	849	6	1.94	5.37	0.68	29.1	5.4	1.01	.288	3.04	66	2.58	60	7.13	40.7
13	Lance McCullers Jr. L. McCullers Jr.	10.26	2021	HOU	28	13	5	.722	28	3.16	185	0	0	0	162.1	122	57	59	13	76	10	0	0	684	7	4.21	2.43	0.72	27.0	11.1	1.22	.273	3.27	74	3.51	83	6.76	13
14	Lucas Giolito L. Giolito	10.13	2021	CWS	31	11	9	.550	31	3.53	201	1	0	0	178.2	145	70	74	27	52	2	0	1	720	12	2.62	3.87	1.36	27.9	7.2	1.10	.269	3.73	81	3.78	85	7.30	13
15	Joe Musgrove J. Musgrove	10.08	2021	SDP	32	11	9	.550	31	3.18	203	2	2	0	181.1	142	64	68	22	54	18	1	3	748	3	2.68	3.76	1.09	27.1	7.2	1.08	.266	3.38	81	3.69	88	7.05	10.2
16	Frankie Montas Jr. F. Montas Jr.	9.96	2021	OAK	32	13	9	.591	32	3.37	207	0	0	0	187.0	164	70	79	20	57	7	0	1	778	11	2.74	3.63	0.96	26.6	7.3	1.18	.296	3.80	82	3.37	81	7.89	16.5
17	Sean Manaea S. Manaea	9.74	2021	OAK	32	11	10	.524	32	3.91	194	2	2	0	179.1	179	78	79	25	41	9	0	0	754	5	2.06	4.73	1.25	25.7	5.4	1.23	.318	3.96	95	3.65	88	8.98	10
18	Nathan Eovaldi N. Eovaldi	9.63	2021	BOS	32	11	9	.550	32	3.75	195	0	0	0	182.1	182	76	81	15	35	7	0	2	764	6	1.73	5.57	0.74	25.5	4.6	1.19	.326	4.00	82	2.78	64	8.98	30.9
19	José Berríos J. Berríos	9.56	2021	TOT	32	12	9	.571	32	3.52	204	1	0	0	192.0	159	75	83	22	45	15	0	0	781	3	2.11	4.53	1.03	26.1	5.8	1.06	.277	3.89	81	3.46	82	7.45	16.5
20	Julio Urías J. Urías	9.45	2021	LAD	32	20	3	.870	32	2.96	195	0	0	0	185.2	151	61	67	19	38	7	0	3	745	2	1.84	5.13	0.92	26.2	5.1	1.02	.272	3.25	73	3.12	73	7.32	23.8
21	Luis Castillo L. Castillo	9.21	2021	CIN	33	8	16	.333	33	3.98	192	0	0	0	187.2	181	83	94	19	75	7	0	4	803	1	3.60	2.56	0.91	23.9	9.3	1.36	.318	4.51	90	3.74	84	8.68	14.5
22	Walker Buehler W. Buehler	9.19	2021	LAD	33	16	4	.800	33	2.47	212	0	0	0	207.2	149	57	61	19	52	6	0	2	815	5	2.25	4.08	0.82	26.0	6.4	0.97	.247	2.64	61	3.15	74	6.46	26
23	Germán Márquez G. Márquez	8.80	2021	COL	32	12	11	.522	32	4.40	176	3	1	0	180.0	165	88	92	21	64	4	0	5	756	15	3.20	2.75	1.05	23.3	8.5	1.27	.293	4.60	91	3.86	87	8.25	11.7
24	Sandy Alcantara S. Alcantara	8.80	2021	MIA	33	9	15	.375	33	3.19	201	1	0	0	205.2	171	73	85	21	50	10	0	2	837	6	2.19	4.02	0.92	24.0	6.0	1.07	.270	3.72	76	3.41	82	7.48	17.2
25	Max Fried M. Fried	8.58	2021	ATL	28	14	7	.667	28	3.04	158	2	2	0	165.2	139	56	61	15	41	7	0	0	667	7	2.23	3.85	0.81	23.7	6.1	1.09	.278	3.31	72	3.30	79	7.55	16.6