submarine pitcher
A baseball pitcher who throws with a sidearm or underhand motion, where the arm drops below the shoulder. The term is used in Japanese baseball commentary and news.
He is a famous submarine pitcher in professional baseball.
A submarine pitcher's delivery is difficult for batters to hit.
Variant with interpunct; less common but seen in some contexts.
Borrowed from English 'submarine pitcher', referring to the low, underhand pitching motion resembling a submarine moving underwater.