Complex sentence: Many baseball players, fans, and administrators view the rules and traditions of professional baseball as time-tested and nearly saate 19th century, when rules changed almost yearly, often significantly.
Split into simpler sentences: Many baseball players, fans, and administrators view the rules and traditions of professional baseball as time-tested and nearly sacrosanct. This was not the case during baseball's early days, particularly in the late 19th century, when rules changed almost yearly, often significantly.