Sinker (SI) vs. Two-Seam Fastball (FT)

Sinker (SI) and two-seam fastball (FT) are kin: low-90s fastballs that move down and into same-handed batters. Same arm action as a four-seamer; the grip along the seams generates the dive.

Statcast (via Pitch Info) used to label them separately, but since the late 2010s the two are usually folded into SI because the distinction is hard to draw consistently.

Velocity sits 1–3 mph below a four-seamer (90–95 mph). The job is to induce groundballs and double plays — opponent BABIP runs higher but extra-base damage is limited.

Where Shota Imanaga lives at the top of the zone, sinker artists like Kyuji Fujikawa and Koji Uehara worked in this contact-management band. Statcast's vertical and horizontal break numbers reveal each pitcher's personality.

→ Related: 4-Seam Fastball / Cutter / Spin Rate