plural of four-seam fastball

(baseball) A pitch thrown with a grip in the "horseshoe" orientation of the ball, with the rotation at a slight angle resulting in less Magnus effect as compared to a four-seam fastball since only two of the ball's seams cross the flight path; the pitch is delivered with a similar velocity as a four-seam fastball, but has a degree of sink.

(baseball) A moderate rotation speed backspin pitch thrown with a ball gripped between the index finger and middle finger; it has good velocity, may have a precessing spin, and sinks as it approaches the plate.

(baseball) A backspin pitch thrown with a ball gripped in the direction to cause four of the seams of the ball to cross the flight path and released with roughly equal pressure by the index and middle fingers