
Castro pitched for 10 years in the majors, coming up with the Milwaukee Brewers in 1974 and finishing with the Kansas City Royals in 1983. Used almost exclusively out of the bullpen, he went 31-26 with 45 saves over his career which also included a brief stint with the New York Yankees in 1981. His best season came for the Brewers in 1977. He was 8-6 that year with a 4.15 ERA and 13 saves. He saved eight more games for Milwaukee in 1978 and finished with a career-best 1.81 ERA.
Following his playing career, Castro was the pitching coach for the Brewers and later for the Baltimore Orioles.
Bill Castro – career stats