noun
ball quality; characteristics of a pitch
Baseball term referring to the perceived weight, movement, or 'stuff' of a pitched ball, often described as 軽い (light) or 重い (heavy).
彼の球質はとても重くて、打ちにくい。
His pitches feel very heavy and are hard to hit.
この投手は球質が軽いので、長打を打たれやすい。
This pitcher's ball quality is light, so he tends to give up extra-base hits.