Complex sentence: After a successful trial during an exhibition series, Pfeffer was signed by the Chicago White Stockings, and he became a fan favorite among the city's German population; they dubbed him "Unser Fritz" ("Our Fritz").
Split into simpler sentences: After a successful trial during an exhibition series, Pfeffer was signed by the Chicago White Stockings, and he became a fan favorite, especially among the city's German population. Fans dubbed him "Unser Fritz" ("Our Fritz").