In 1961, Slack began a 24-year career as a manager and roving minor league pitching instructor in the Red Sox farm system. He spent much of that time with the Winston-Salem Red Sox, Boston's Class A Carolina League affiliate, managing them for 13 years (1963–68, 1970, 1973–74, 1978–79 and 1983–84), and winning four pennants. He also led the Bristol Red Sox to the Double-AEastern League championship in 1975 as a late-season replacement for manager Dick McAuliffe, who had been recalled to Boston as an active player. He won 1,120 games and lost 1,065 (.513) as a manager in the Boston system (not including his brief Bristol tenure).
Slack, who had become a full-time resident of Winston-Salem, joined the Braves in 1985 when the Red Sox left the Carolina League. He served as a minor league pitching coach for Atlanta farm clubs at the Class A and Double-A levels for another 14 years, through 1998. After two years in retirement, he briefly managed the Savannah Sand Gnats of the Class A South Atlantic League in 2001, and was the pitching coach of the Wilmington Blue Rocks of the Carolina League for two seasons (2002–03).
A native of Petrolia, Ontario, Slack was named to the Canadian Baseball Hall of Fame in 2002. The Winston-Salem Dash in his adopted city present the Bill Slack Community Service Award every year in his honor.
References
^Howe News Bureau, Boston Red Sox 1983 organization book