As manager Frank Lee Duncan Jr (February 14, 1901 – December 4, 1973) was an American baseball player in the Negro leagues from 1920 to 1948.

He was primarily a catcher for the Kansas City Monarchs, handling their pitching staff for over a decade.

Duncan broke in with the 1920 Chicago Giants, forcing John Beckwith to move from catcher to shortstop.

In 1922, Duncan improved to .235/.317/.313 at the plate and was credited with 22 sacrifice hits to lead the Negro National League in that category.

Despite the low batting average, one of his most memorable moments as a player came in Game Eight when he singled the tying and winning runs home in a dramatic ninth-inning comeback victory by his team.

The play was notable because veteran catcher Louis Santop had dropped Duncan's foul pop-up one pitch before, and his key hit went through shortstop Biz Mackey's legs.

He again had a huge moment in the series, with a great tag on Otto Briggs at home in the 11th inning of game one.

Duncan took part in a memorable tour of Japan by Negro league players that year; the blackball stars won 23 games, tied once and lost none.

He became Kansas City's playing manager in 1942, leading them to a league title, and then won the 1942 Negro World Series, sweeping the Homestead Grays four games to none.

Duncan was drafted into the United States Army for World War II after the 1942 season.

He showed off his precision by hitting 31 bull's eyes in 32 shots in rapid firing from 200 yards, a marksmanship record.

In 1944, at 43 years old, he hit .144, and the Monarchs finished last for the first time in their history, having lost much of their best players to the war.

Duncan led Kansas City to the 1946 Negro World Series, which they lost in seven games to the Newark Eagles.