In 1883, the number was increased to 11, which was a typical roster size in that era, and soon teams were allowed unlimited reserves.

In 1882, Soden served briefly as president of the National League (NL) following the death of William Hulbert.

Soden played a major role in the war between the NL and the Players' League in 1890, bankrolling several teams in the league as attendance dropped; by the time the NL emerged triumphant, Soden owned a majority of the New York Giants in addition to his control of the Boston franchise.

After losing the pennant to Baltimore in 1894 and 1895, a struggling start in 1896 led Soden to observe that his players' on-field arguments were having a negative effect, and stated that any players fined for abusing umpires would now pay their own fines rather than have the team cover the cost secretly; Boston went on a 22–2 run over the next few weeks, and briefly took over first place, but finished behind Baltimore (for the last time) that season.

Soden was known for being stingy, and catcher Boileryard Clarke observed after coming to the Beaneaters from Baltimore in 1899 that the team owner was also amazingly distant.