During his playing days, Flowers stood 6 feet 4 inches (1.93 m) tall, weighed 195 pounds (88 kg) and batted and threw right-handed.

Flowers, a knuckleball pitcher, debuted in the major leagues with the Boston Red Sox, appearing in 33 games pitched, one in 1951 and 32 during the full season of 1953.

His most productive season came for the 1953 Red Sox, when he posted career-bests in earned run average (ERA) (3.86), strikeouts (36), and innings pitched (871⁄3), in 32 games, including six starts, and one shutout, while recording all three of his career saves.

His lone big-league shutout and complete game happened on August 5, when he blanked the St. Louis Browns, 5–0, at Fenway Park, allowing eight hits and two bases on balls.

[2] The losing pitcher in that contest was Don Larsen, later to be immortalized as a New York Yankee by his perfect game during the 1956 World Series.