What is an Immaculate Inning? Definition and Examples
An immaculate inning is a half-inning in which one pitcher strikes out all three batters on exactly nine pitches — every pitch a strike, no contact, no balls.
Plain-English Definition
An immaculate inning is a half-inning in which a single pitcher records three strikeouts on exactly nine pitches. Every pitch must be a strike, and every batter must go down swinging or looking on the third one. No foul-outs, no balls in play, no walks, no hit-by-pitches, and no balls in the count for any of the three batters. It is the pitching equivalent of a perfect quarter of an inning — the cleanest, most efficient strikeout sequence the game allows.
How It's Measured
The criteria are deterministic:
- 3 batters faced
- 9 pitches thrown by the same pitcher in the same half-inning
- 9 strikes (called or swinging — fouls and whiffs both count)
- 3 strikeouts as a result
Every pitch must be a strike. A single ball, foul-out, ball put in play (even for an out), or pitcher change disqualifies the inning. Because strike three cannot be a foul ball, the third pitch to each batter must be either swinging strike three or called strike three.
Worked Example
On May 14, 2023, Max Scherzer of the Mets struck out the side on nine pitches against the Nationals — his career second immaculate inning. The sequence: three pitches, three batters, three Ks, zero balls. Scherzer used a fastball/slider/changeup mix and got two swinging strikeouts and one looking.
Through the end of the 2024 season, there have been roughly 120 immaculate innings in MLB history since John Clarkson reportedly threw the first in 1889. Sandy Koufax did it three times. Modern multi-time members include Felix Hernandez, Max Scherzer, and Chris Sale. Spencer Strider added one in 2023; Shohei Ohtani recorded one as a pitcher in 2022. The pace has accelerated dramatically — more than half of all immaculate innings in history have occurred since 2010, mirroring the league-wide strikeout boom.
Why It Matters
The immaculate inning is not a stat front offices optimize for, but it is a signature of elite swing-and-miss stuff combined with command on a given night. The pitchers who throw them tend to score well on Stuff+, Pitching+, and CSW — they generate whiffs *and* called strikes, the two outcomes that drive a 0–0 count to a strikeout in three pitches.
For fans, it is a tracked milestone alongside no-hitters and perfect games. Broadcasters flag the possibility live the moment a pitcher starts an inning 0–2, 0–2 on consecutive hitters. For sabermetric writers, frequency trends are a clean proxy for the league strikeout rate: when K% rises, immaculate innings rise faster than linearly.
Limitations and Common Misconceptions
- It is not a "perfect inning." A perfect inning is any 1-2-3 inning regardless of pitch count or outcome type. An immaculate inning is a strict subset.
- It does not require swinging strikeouts. Called third strikes count. A pitcher can throw nine called strikes and qualify.
- The third strike cannot be a foul. Many would-be immaculate innings die on a 0-2 foul tip that the catcher does not glove.
- It is not a team record. Only one pitcher can hold an immaculate inning — a mid-inning pitching change resets the count of pitches for the inning.
- It does not require triple-digit velocity. Greg Maddux-style command works as well as Strider-style heat; the requirement is strikes, not speed.
Related Terms
In Legends Deck
In Legends Deck, pitcher cards with elite Stuff and Command ratings — typically 90+ on both — are the only realistic candidates to simulate an immaculate inning. The sim engine resolves each pitch against the hitter's whiff rate and chase rate, and players can chase the achievement across season-long franchise mode. Spencer Strider and Jacob deGrom cards have produced the highest simulated immaculate-inning rates in our internal testing.