A small, fireballing strikeout artist, Barnhill was the ace of the New York Cubans‘ staff during the early 1940s, compiling an 18-3 record in 1941. He pitched in the 1941-43 East-West all-star games, defeating Satchel Paige in the 1942 contest. That year, the Pirates considered Barnhill for the role of breaking baseball’s color line, but the opportunity did not materialize. In 1947, he shut out the Cleveland Buckeyes in the Negro World Series to help the Cubans to the championship. He was signed by the New York Giants in 1949, and in 1950 he compiled an 11-3 record for the AAA champion Minneapolis Millers (American Association). Since he was already 35, his age kept him from getting a shot at the majors. He continued to play in the Pacific Coast League and Florida International League until 1953.