[David Ball]

Yes, in 1872 the Eckfords signed a number of Troy players after Troy folded. I had forgotten about Treacey signing with Philadelphia after the Centennials went under. As far as we know, the Philadelphias were able to do that after the Athletics had paid for the Centennials to disband, so the Phillies got a freebie. However, it wouldn't be surprising if the Phillies also kicked in some money to get the man they wanted while the Athletics got their two. All three clubs seem to have been on pretty good terms with one another, and there were interrelationships among their management, which no doubt facilitated such a deal.

The Centennials were founded as a third team in Philadelphia that was to be based on cheap young local talent, of which Philadelphia had a lot. There was to be a big festival in Philadelphia the next year to celebrate the centennial of the Declaration of Independence, and they hoped to draw tourists coming to the festivities to their games. From one newspaper item I've seen, it looks as though the idea may have been to play through 1875 with a cheap team and then strengthen in 1876, when receipts would presumably increase. In the event, the centennial celebration did nothing positive for professional clubs in Philadelphia, all three of whom were gone by the end of the 1876 season, and the conventional wisdom ended up being that, rather than bringing in more potential spectators to town, the centennial had distracted attention from baseball by providing counterattractions.

At any rate, the Centennials did not make it to 1876, and besides the youngsters, they wound up signing the veterans Craver, Bechtel, Treacey and Radcliffe, and it's probably not coincidence that all four of them were suspected of game-throwing and among them had a rich history of contract jumping, drinking, etc., etc., etc., and were near the end of their careers. The Centennials must have been one of the co-op teams, that is, a club that paid its players a percentage of the receipts rather than a salary. Established players did not like playing for a team like that if they had an alternative, but the veterans the Centennials got were all men that strong teams would have stayed away from, so they didn't have a lot of alternatives.

Before the season the Centennials were considered the best of the co-ops, probably a reasonable assessment of their quality -- if I remember correctly, they won their one game with New Haven pretty handily. But they mostly scheduled the best teams, Boston and their Philadelphia rivals and as a result got blown out pretty regularly. They were the first team to fold and had players of talent who were of interest to the other weak clubs, so they scattered pretty widely.

This was before the era of the reserve clause, so pretty nearly all the players were free agents at the end of every season. In the summer of 1875 Chicago staged a big raid on the Boston roster and signed four star players for the next season, and they also signed Cap Anson from the Athletics, so that accounts for some of the turnover, but there wasn't anything different in principle from what had happened in previous years. In order to provide stability, Boston did make a practice of signing some players to multiyear contracts, and other teams did at least a little of this, but not a lot of information survives. In any given offseason, though, the great majority of players must have been free agents.

It helps, by the way, to refer to the Athletics by that formal name, rather than calling them Philadelphia, which causes confusion with the team officially known as the Philadelphia club. If you're interested in the NA, I would strongly recommend William Ryczek's history of it, Blacklegs and Stockings.