Ratkovicz's pro career began when he was 19 years old, playing 13 games for the Chicago Bruins of the National Basketball League during the 1941–1942 season.

Playing alongside future Basketball Hall of Famers Dolph Schayes and Al Cervi, Ratkovicz averaged eight and a half points per game in his first NBA season[3] and played in the NBA Finals, where the Nationals lost to the Minneapolis Lakers in six games.

[3] Ratkovicz's role was reduced during the 1951–1952 season; playing in twenty and a half minutes a game, he averaged seven and a half points and five rebounds per game while serving as a backup to Dolph Schayes.

That season, he averaged nine-and-a-half points and nearly seven-and-a-half rebounds per game.

[3] Ratkovicz died in Webster, New York on November 10, 2008, three days before his 86th birthday.