He played his league debut in the La Chaux-de-Fonds team in the 1933–34 Nationalliga season.
In the 1935–36 Nationalliga season he played in all 26 league games scoring 16 of the team's 47 goals, saving his team from relegation as they ended the season in 12th position just one point above the relegation slot.
The replay was played in the Stadion Neufeld in Bern on 20 June 1937 and ended in a 1–0 victory for Basel and La Chaux-de-Fonds were relegated.
[1] Schaller moved on and joined Basel's first team for their 1937–38 season under player-manager Fernand Jaccard.
After playing two test games, Schaller made his domestic league debut for his new club in the home game at the Landhof on 29 August 1937 as Basel won 1–0 against Young Fellows Zürich.