The comments of The Clipper on baseball matters in St. Louis have had the effect of creating quite a little stir there in regard to the organization of nines to take part in the coming campaign of 1875. One result is a proposition to organize another professional nine as a local rival to the St. Louis stock company club, the new club to be run on the co-operative principle. Nothing better could be devised in the interest of the St. Louis Baseball Association than the organization of just such a rival team. The advent of the Philadelphia nine in 1873 put thousands of dollars into the pockets of the Athletics, and the new Centennial nine of that city ought to help both the Philadelphia and Athletic nines this year, if it is properly managed. There is nothing like rivalry to give interest to baseball contests. Heretofore the West has had too little rivalry; but this coming season there will be plenty of it, ,what with the Chicago "Whites," the St. Louis, the Western Keokuks, and the new St. Louis "Cops," as the co-operatives are called. The St. Louis stock company "regulars," it is proposed, shall be opposed by a co-operative nine composed of local players. This will impart considerable interest to a series of matches between the eastern imported stock and the western native material. The St. Louis club would by all means encourage the organization of the nine in question, and give them a chance to play upon their grounds.-Mears Baseball Scrapbook, Volume Four, 1856-1907
This article raises a lot of questions. Dating the articles in the Mears Collection can be a bit tricky and, to the best of my knowledge, this appeared in the Clipper in November of 1874, which throws a wrench into my thinking about when and why the Reds joined the NA.
The best available research shows that, in January of 1875, the Reds had still not made the decision to join the NA and that the decision wasn't made until February. I believe that the reason the Reds eventually made the decision to join the professional ranks was that the Brown Stockings decided to play their home games at the Grand Avenue Grounds rather than the Compton Avenue Grounds, which was operated by Thomas McNeary. McNeary, who also operated the Reds, was one of the early investors in the Brown Stockings and, I believe, had every intention of getting the new club to play at his ballpark. In late November of 1874, the Brown Stockings had still not decided on a home ground. Based on all of that information, my thinking has been that sometime in late 1874 or early 1875, the Brown Stockings decided to play their home games at the Grand Avenue ballpark and McNeary then began to consider the option of placing the Reds in the NA. Even with the Brown Stockings playing on Grand, if McNeary entered the Reds into the NA, he would still have professional baseball, and the draw of the big professional clubs, at his ballpark. The whole thing was about drawing fans to the Compton Avenue Grounds and making money. McNeary's plan A, having the Brown Stockings play at his ballpark, fell through and he moved on to plan B, having the Reds play in the NA.
This article, however, brings all of that into question. According to the Clipper, the idea of having another professional team in St. Louis, operating on the co-operative plan, dates to November of 1874, when the Browns had still not made up their minds about where to play. The Clipper suggests that the whole scheme was about producing rivalries, building up interest in the game and, one would imagine, drawing more fans and making more money. It's also insinuated that the idea for a second St. Louis team came from the Eastern baseball press (Henry Chadwick?) rather than being something that sprung up locally. There is nothing here that suggests a fallout between the Brown Stockings and McNeary.
There is also nothing here that specifically mentions the Reds. It's possible that the idea of a second club predated McNeary's decision to enter the Reds into the NA and he took up the idea after a previous attempt to organize a co-op club (the St. Louis Cops) failed. It's possible but unknown. The most likely explanation of all of this is that the Clipper is talking about the Reds but it's not it's not conclusive.
What we now know for a fact, however, is that the idea of a second St. Louis club competing in the NA in 1875 dates from November of 1874.