After a 16-year major-league career, left-handed reliever Andrew Miller told the St. Louis Post-Dispatch on Thursday he was retiring.

Miller, 36, was a free agent after spending the past three seasons with the St. Louis Cardinals. He began his career as a middling starter with the Tigers, Marlins and Red Sox, but after transitioning to a bullpen role in Boston he became dominant with over 14 strikeouts per nine innings in four consecutive seasons.