Late in the 1940 season, NL umpire Bill Klem was unable to work due to an ankle injury, so Barlick was hired as a replacement. He made his debut in a doubleheader at Shibe Park on September 8. Barlick was offered a contract for the 1941 season, and was 26 years old at the start of the season, making him one of the youngest MLB umpires in history. Before the 1941 season, Klem had strongly endorsed Barlick, saying, "He's going to be the greatest umpire in baseball history. He has a love of his work, a pride in it and the physical qualifications. Young? Certainly. But there's something wrong with an umpire who serves a long time in the minors."