Mr. A. Blong has gone to Philadelphia to look after the interests of the Red Stockings and will act as their delegate on the admission of the club into the Professional association.
-Missouri Republican, February 28, 1875
Let's go over the timeline of events and see what we can learn:
-November 1874: Thomas McNeary is at the first meeting of the Brown Stockings organization and subscribes to stock in the St. Louis Base Ball Club.
-Late November 1874: There are reports in the St. Louis papers that the Brown Stockings were negotiating to build a new baseball grounds somewhere "very near the city..."
-Late November 1874: The Clipper reports that a St. Louis co-op club would enter the NA, alongside the Browns. No specific mention of the Reds but the description fits exactly what the club did.
-Late January 1875: Rumors surface in the St. Louis papers that the Reds were going to enter the NA.
-February 1875: The Reds join the NA.
When we lay it out like this, the events of late November 1874 certainly stand out and it appears as if the Browns could have rejected McNeary's offer to have the club play his ballpark at that time, leading to speculation that McNeary would have the Reds join the NA. But I'm not sold on the idea that events moved that fast. First, the report in the Clipper was not solid. They talked about a "proposition" to have another St. Louis club join the NA - not the fact that it was happening. Also, the Browns were in negotiations about a new grounds and had not committed to build one, as they, in fact, did not. It was still up in the air, in late November, as to where the club would play its home games.
I don't think anything had been decided by late November 1874 and it's very possible that the information in the Clipper was meant as shot across the bow of the Brown Stockings. McNeary may have been letting them know that there was going to be a professional NA club at Compton Avenue, one way or another. Also, remember that the Repbulican reported in late January that "nothing official" had been decided regarding the Reds.
So where does that leave us? My thinking is that McNeary didn't make a decision about the Reds until December at the earliest but, at this point, I should amend this by saying that he was thinking and planning to have an NA club at his park in early November 1874. His original plan appears to have been to have the Browns play at Compton Avenue but, failing that, he would have the Reds enter the NA. The one piece of information that I don't have that I need is the date that the Browns decided to play their home games at the Grand Avenue Grounds. That would tell us a lot. But the important point is that, by the end of the 1874 season, McNeary was thinking about having a professional NA club at the Compton Avenue grounds.