[2][3] While in college, he also played minor league baseball for the Duluth Dukes, Jamestown Falcons, Rochester Red Wings, Lynchburg Cardinals and Allentown Cardinals, posting a .266 batting average with 42 home runs and 242 runs batted in in 400 games.

[4] This arrangement attracted controversy during the 1944–45 season, since it was regarded in some quarters as a violation of his amateur status for college basketball.

[5][6] Following his college career, Seltz joined the Anderson Duffey Packers of the National Basketball League (NBL) in 1946.

He made his NBA debut for the franchise on November 3, 1949,[2] scoring 18 points and making four of five free throws against the Tri-Cities Blackhawks.

He was part of the team that won the Class-A championship in 1949,[9] and was honored as the tournament's most valuable player after batting .643 and committing no errors in 27 chances.