Although Masi was considered one of the best defensive catchers of his era, he was also notable for his involvement in a controversial play that occurred during the 1948 World Series between the Boston Braves and the Cleveland Indians.

[1] Born in Chicago, Masi attended Austin High School, then began his professional baseball career when he was contracted in 1936 by the Cleveland Indians at the age of 20.

[7] The Bees already had future Hall of Fame member, Al López, as well as future All-Star, Ray Mueller and veteran Johnny Riddle as catchers going into spring training in 1939 however, Masi impressed Bees' manager Casey Stengel so much that, Mueller and Riddle would be traded before the start of the season, leaving Masi as Lopez's backup.

[2][11] Masi served as the Braves' backup catcher first to Al López, then Ray Berres, and finally to Ernie Lombardi.

[16] Masi was hitting for a .300 average in late June 1946, earning him a place as a reserve player for the National League in the 1946 All-Star Game.

[1] In 1946, pitchers Warren Spahn and Johnny Sain returned to the Braves from their military service and, their success further enhanced Masi's reputation for handling pitching staffs.

[1][22] Masi guided the Braves' pitching staff to a league-leading 14 shutouts and the second-best team earned run average in the league, as both Spahn and Sain won 21 games each.

[25] Although Masi's offensive output began to decline in 1948, he earned his fourth consecutive All-Star selection due to his excellent defensive abilities.

[1] It was in the first game of the 1948 World Series held at Braves Field against the favored Cleveland Indians that Masi would become embroiled in a controversy that secured his place in baseball history.

[30] The umpire's controversial ruling touched off heated debates among the media and fans, especially after Associated Press photographs of the play were published.

[1] In 1951, Masi's experience was again evident as he helped the White Sox pitching staff improve their earned run average to second best in the American League behind the Cleveland Indians.

[1] When the White Sox acquired a younger Sherm Lollar in 1952, Masi returned to backup duties before being released at the end of the season.