From Jorge Figueredo’s Cuban Baseball (p. 7):
On December 21, [1879,] an American team named the Hop Bitters, headed by Cincinnati promoter Frank Bancroft, visited Havana and easily disposed of a Cuban squad that scored a single run by Carlos Zaldo, who got on base following a successful bunt, the first native player to master this particular craft.
In Cuba the team was indeed promoted as the “Hop Bitters,” a name usually associated with Rochester, New York. And in fact the trip appears to have been financed by a “Mr. Soule of Rochester, N.Y.” (New York Clipper, November 29, 1879). But it turns out that Bancroft’s team was really, as the Clipper remarked in its November 29 issue, “composed entirely of the Worcesters of 1880”—that is, the Worcester, Massachusetts, club of the (minor) National Association of 1879, with the players they intended to use the following season. The Worcesters joined the National League for the 1880 season, and would play there through 1882 (they are called in all the reference books the “Worcester Ruby Legs,” though I’m not sure how prevalent that nickname was at the time); so the nine that visited Cuba in 1879 was, if not technically a “major league” club, practically one. The latest standings I could find for the 1879 NA shows the Worcesters at fourth place of nine clubs with a 19-23 record. In 1880 they would fare about the same in the NL, at 40-43 and fifth (though with Lee Richmond and Fred Corey added on the mound, and Harry Stovey in the outfield). The roster is listed in the Clipper (November 22, 1879); here is the passenger manifest for their return to the United States, arriving at New Orleans on December 31:
Seven of these players (all but Foley, who would go to Boston, and Nichols, who would only pitch two games for Worcester) would be regulars for Worcester in 1880.
The trip was not a financial success. As far as I can tell, they ended playing only two games in Cuba, spending the rest of the winter in New Orleans. This piece, from the Clipper (January 3, 1880), explains it from the American point of view:
It’s important to remember that the United States had made several attempts to acquire Cuba, most recently offering to purchase the island in 1869, just after the Ten Years’ War, a Cuban rebellion, had begun. Baseball, probably considered a symbol and symptom of U.S. subversion, was banned by Spanish authorities in that same year (though the ban was apparently flouted often, or only intermittently enforced). In 1873, war had nearly broken out between the United States and Spain over the “Virginius Affair,” a Bay of Pigs-like incident involving an American-manned ship caught attempting to smuggle arms, ammunition, revolutionary leaders, and about 100 soldiers into Cuba (you will be hearing more about this soon). When the Worcester players visited in 1879, the Ten Years’ War had been over for only a year, and the atmosphere they encountered was surely tense.