Chase Rate
Also known as: O-Swing%, swings outside the zone
Chase rate is the percentage of pitches thrown outside the strike zone that a hitter swings at — a core plate-discipline metric where lower is almost always better.
Chase rate isolates one specific decision: given a pitch outside the strike zone, did the hitter swing at it? Because pitches outside the zone are, by definition, harder to hit productively — they are farther from the hitter's ideal contact zone and often the pitcher's intended location to induce weak contact or a miss — a lower chase rate generally correlates with better overall offensive performance across almost every level of the sport.
Chase rate isn't just a discipline score in isolation; it interacts heavily with count. Hitters chase more often in two-strike counts because the cost of taking a borderline pitch rises sharply, which is expected and appropriate — the more meaningful signal is chase rate in early or neutral counts, when there is no urgency forcing an expanded zone. A hitter who chases heavily even in favorable counts has a pitch-recognition or patience issue distinct from the situational expansion that comes late in counts.
Chase rate also varies meaningfully by pitch type, and breaking it down that way is more useful than a single aggregate number. A hitter who rarely chases fastballs out of the zone but chases breaking balls heavily has a specific spin-recognition weakness that a blended chase rate would hide.
Example
His overall chase rate looked reasonable, but broken down by pitch type it revealed he chased sliders out of the zone far more than any other pitch.
Why it matters
Chase rate is one of the most predictive plate-discipline indicators available, and it is measurable from any pitch-tracked at-bat. SwingVantage breaks chase rate down by count and pitch type to find the specific pattern behind an aggregate number.
Common mistakes
- Looking only at an aggregate chase rate instead of breaking it down by count and pitch type
- Judging chase rate in two-strike counts the same way as in early counts, when some expansion is appropriate and expected
- Ignoring chase rate entirely because a hitter's batting average looks fine — plate discipline erosion often shows up before results do
Frequently asked questions
What is a good chase rate?
It varies by level and pitch mix, but broadly, a lower chase rate on non-two-strike counts indicates stronger plate discipline. The most useful read compares a hitter to their own history and to their peer level, not to a single universal number.
Is chasing pitches always bad?
Not always — a two-strike count appropriately expands the zone a hitter is willing to defend. The concerning pattern is chasing at a high rate in counts with no urgency to expand.
Related terms
- Whiff RateWhiff rate is the percentage of swings that result in no contact at all — distinct from chase rate, which measures the decision to swing, whiff rate measures what happens once the swing is already committed.
- Plate DisciplinePlate discipline is the ability to distinguish balls from strikes and to swing only at pitches where the hitter can do damage — the foundational mental skill of hitting.
- Called Strike RateCalled strike rate is the percentage of pitches in the strike zone that a hitter takes for a strike rather than swinging at — the mirror image of chase rate, measuring missed opportunity rather than bad swings.
- Check SwingA check swing is a hitter starting the swing motion and then stopping the bat before it crosses the plane of contact, most often to hold off on a pitch recognized late as a ball — its legality by the rulebook comes down to whether the bat and wrists broke toward the ball.
Related guides & benchmarks
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