How to Read a Pitch Movement Chart

The movement chart is the most information-dense graphic in a pitching report and the one most likely to get skipped because nobody explained the axes. It is worth ten minutes of your time — once it clicks, you can read a pitcher’s entire arsenal at a glance.

A movement chart plots each pitch as a dot on two axes: horizontal break left-to-right, and induced vertical break bottom-to-top. Each pitch type forms its own cluster. The picture that emerges tells you how a pitcher’s pitches separate from one another — or fail to.

Both axes are measured in inches, and both describe movement caused by spin, not by gravity. That last part is the piece that trips people up.

A four-seam fastball with high induced vertical break is often described as a "rising fastball." No pitch rises. Every pitch falls, because gravity is undefeated.

Induced vertical break (IVB) measures how much a pitch deviates from a spin-less path — how much the ball fought gravity, not how much it beat it. A fastball with 18 inches of IVB still drops on the way to the plate; it just drops about 18 inches less than a ball thrown with no backspin would. Since a hitter’s brain is calibrated to expect a certain amount of drop, that gap is what produces swings under the ball.

So on the chart:

• High positive IVB (top of the plot) — backspin fighting gravity. Four-seam fastballs live here.
• Near zero — the pitch drops about as much as physics dictates. Changeups and splitters sit around here.
• Negative IVB (bottom of the plot) — topspin adding drop beyond gravity. Curveballs live here.

Horizontal break measures side-to-side movement, again from spin alone. The complication: it is measured in a fixed frame, so the same pitch thrown by a righty and a lefty shows up with opposite signs.

The fix is to think in terms of arm side and glove side rather than left and right:

• Arm-side run — movement toward the pitcher’s throwing arm. Sinkers, two-seamers, and changeups run arm side.
• Glove-side cut — movement toward the glove hand. Sliders, cutters, and sweepers move glove side.

When you compare two pitchers of opposite handedness, compare the size of the movement, not the raw signed number — otherwise a lefty and a righty with identical sliders will look like opposites.

You are looking for two things, and they matter in this order.

First, separation. Pitch clusters should sit far apart on the plot. If a pitcher’s slider and cutter overlap in the same region, they are functionally the same pitch to a hitter no matter what they are labeled — that is a real finding, and usually means one of them needs to change shape or be scrapped.

Second, tightness. A single pitch type should form a compact cluster. A slider scattered across a wide area of the plot is inconsistent — the pitcher is not repeating the same shape, which usually traces back to release inconsistency. A tight cluster means the pitch is repeatable, which is what makes it trustworthy in a big count.

Movement is not the same as effectiveness. A pitch with enormous break that the pitcher cannot locate is worse than a modest one he commands. The movement chart tells you what a pitch does, not where it goes or whether hitters miss it — read it alongside location plots and CSW% before drawing conclusions.

Velocity also matters to how movement plays. Twelve inches of arm-side run at 94 mph is a different pitch than the same run at 84 mph, because the hitter has far less time to adjust. Most movement plots encode velocity somehow — in a tooltip or by dot size — so check it before judging a cluster.