 Irabu pitched for the Lotte Orions, who later became the Chiba Lotte Marines, of the Pacific League from 1988 to 1996.He was known as a high-speed pitcher and in 1993, he threw a 158 km/h (98 mph) fastball against Kazuhiro Kiyohara of the Seibu Lions.This was the fastest clocked pitch in all of Japanese Professional Baseball (NPB) until 2005, when the record was broken by Marc Kroon of the Yokohama BayStars.