Player stats

Strikeouts per 9 Innings 2021

Strikeouts per nine innings pitched. Unlike K%, the denominator is innings rather than batters faced.

Season

Minimum workload: one inning pitched per game. Completed seasons use the league's scheduled regular-season game count; seasons in progress use team games played. This is a general pitching minimum, not a relief-pitcher qualification rule. Data through December 31, 2021. Data refreshed Sep 12, 2026, 7:39 AM UTC.

No. 1 / Strikeouts per 9 Innings / 2021

Corbin Burnes

MIL

12.61

Season leader

Strikeouts per 9 Innings2021 season
#	Player	Team	IP	BF	K/9
1	C. BurnesCorbin Burnes	MIL	167.0	657	12.61
2	D. CeaseDylan Cease	CWS	165.2	708	12.28
3	G. ColeGerrit Cole	NYY	181.1	726	12.06
4	M. ScherzerMax Scherzer	LAD	179.1	693	11.84
5	R. RayRobbie Ray	TOR	193.1	773	11.54
6	A. NolaAaron Nola	PHI	180.2	749	11.11
7	Y. DarvishYu Darvish	SD	166.1	681	10.77
8	K. GausmanKevin Gausman	SF	192.0	775	10.64
9	B. WoodruffBrandon Woodruff	MIL	179.1	708	10.59
10	T. MahleTyler Mahle	CIN	180.0	759	10.50
11	C. MortonCharlie Morton	ATL	185.2	756	10.47
12	Z. WheelerZack Wheeler	PHI	213.1	849	10.42
13	L. McCullers Jr.Lance McCullers Jr.	HOU	162.1	684	10.26
14	L. GiolitoLucas Giolito	CWS	178.2	720	10.13
15	J. MusgroveJoe Musgrove	SD	181.1	748	10.08
16	F. MontasFrankie Montas	OAK	187.0	778	9.96
17	S. ManaeaSean Manaea	OAK	179.1	754	9.74
18	N. EovaldiNathan Eovaldi	BOS	182.1	764	9.63
19	J. BerríosJosé Berríos	TOR	192.0	781	9.56
20	J. UríasJulio Urías	LAD	185.2	745	9.45
21	L. CastilloLuis Castillo	CIN	187.2	803	9.21
22	W. BuehlerWalker Buehler	LAD	207.2	815	9.19
23	G. MárquezGermán Márquez	COL	180.0	756	8.80
24	S. AlcantaraSandy Alcantara	MIA	205.2	837	8.80
25	M. FriedMax Fried	ATL	165.2	667	8.58
26	A. DeSclafaniAnthony DeSclafani	SF	167.2	676	8.16
27	M. StromanMarcus Stroman	NYM	179.0	730	7.94
28	K. GibsonKyle Gibson	PHI	182.0	754	7.66
29	H. Jin RyuHyun Jin Ryu	TOR	169.0	701	7.62
30	A. WainwrightAdam Wainwright	STL	206.1	828	7.59
31	P. CorbinPatrick Corbin	WSH	171.2	751	7.50
32	J. LylesJordan Lyles	TEX	180.0	769	7.30
33	T. AndersonTyler Anderson	SEA	167.0	703	7.22
34	W. MileyWade Miley	CIN	163.0	690	6.90
35	K. HendricksKyle Hendricks	CHC	181.0	785	6.51
36	Z. GreinkeZack Greinke	HOU	171.0	697	6.32
37	C. IrvinCole Irvin	OAK	178.1	768	6.31
38	C. FlexenChris Flexen	SEA	179.2	741	6.26
39	D. KeuchelDallas Keuchel	CWS	162.0	720	5.28

K/9: Strikeouts per nine innings pitched. Unlike K%, the denominator is innings rather than batters faced.

Understanding Strikeouts per 9 Innings

Strikeouts per nine innings pitched. Unlike K%, the denominator is innings rather than batters faced.

Formula: 27 × SO ÷ outs recorded

Read rates alongside playing time. A small sample can produce an extreme result, and a missing value is different from zero.

Season rankings use regular-season records. A player has one combined row across teams; the team label identifies the associated team, not a separate team stint.

Source: MLB statistics and MLBDB derived measures. Formulas describe the measure above. Data refreshed Sep 12, 2026, 7:39 AM UTC.