Screwball

aka scroogie · fadeaway (historical, Christy Mathewson's term)

A pitch that breaks the 'wrong' way, in toward a same-handed hitter, the opposite of a curve. It's thrown by twisting the wrist backward from how a curve is thrown. One of the rarest pitches in the game, and it has nearly disappeared.

Schematic baseball cover. This pitch has no filed seam geometry yet — the grip and shape below are sourced in words, not measured here.

The grip

Thrown with the forearm and wrist pronating the 'wrong' way at release — a right-hander turns the hand clockwise and a left-hander counter-clockwise — the reverse of the supination used on a curve.

Reputable analysisScrewball — Wikipedia

What it does

Breaks in the opposite direction of a curveball or slider, moving in toward a same-handed hitter. It is one of the rarest pitches in the game and now nearly extinct — a longstanding belief that the unnatural pronation wrecks arms has kept most pitchers away, a reputation SABR's analysis of Carl Hubbell pushes back on while noting the prejudice persists; Hubbell and later Fernando Valenzuela were its great practitioners.

Reputable analysisHubbell's Elbow: Don't Blame the Screwball — Society for American Baseball Research

The 'fear of arm injury keeps it nearly dead' framing is the prevailing belief rather than settled medical fact — the SABR article explicitly argues the screwball was wrongly blamed for Hubbell's elbow. No injury or medical claim is asserted here, only the pitch's reputation and rarity.

Who throws itCarl Hubbell, Fernando Valenzuela, Christy Mathewson

Basic file

This pitch has a sourced one-line grip and movement and an honest explanation — not yet a filed specimen with authored grip geometry and a full craft chapter. A fuller breakdown is coming. Sourced, not corrected.