A Manhattan-based yachting team known as Metropolitan Club was in existence and covered by The New York Times in the 1850s, yet it remains very murky whether or not such a commonplace name as “Metropolitan” can really draw a 40-year link between two radically different sports & contexts.
The Metropolitan Club was founded in 1880 as an independent professional team by business entrepreneur John B. Day and baseball manager Jim Mutrie. Unusually for professional teams of the period, the Mets had an actual name and were listed in standings and box scores as "Metropol'n" as opposed to "New York." Initially the team played its games in Brooklyn and in Hoboken, New Jersey as the other New York area clubs did at the time. However, by September, Day had arranged the use of a polo field just north of Central Park in Manhattan, bounded by 5th & 6th Avenues and 110th & 112th Streets. The site became known as the Polo Grounds because polo was initially played there. The Polo Grounds was the first professional baseball park in Manhattan.
The club name, "Metropolitan", had previously been used by an amateur club that played its home games in the Hamilton Square neighborhood of New York as early as 1858.
The National League had expelled the Mutual Club of New York following the 1876 season for failing to make their final road trip of the year and by 1881 had still not replaced them with another New York City franchise. The upstart American Association therefore saw a significant opportunity when it invited the Metropolitan to join the new league for its 1882 inaugural season. Metropolitan declined, however, since joining would have meant forgoing lucrative home exhibition games against National League opponents.
Because of Metropolitan's financial success at the Polo Grounds, and because each league knew that it needed a successful New York City franchise to compete against the other, at the end of 1882 both leagues tendered franchise offers to the Mets. Unbeknownst to the leagues, though, the Mets accepted both invitations. To satisfy these commitments, owners Day and Mutrie acquired the Troy franchise that had been eliminated from the National League (along with Worcester) to make room for new franchises in New York City and Philadelphia. Day and Mutrie entered the Mets into the American Association and a newly created New York team into the National League. The teams shared use of the Polo Grounds, which was reconfigured with two diamonds and two grandstands.
The club's name "Metropolitan" was used in published standings of the Association, while the name "New York" was used for the National League entry. In the style of the day, the clubs were often called the "Metropolitans" and the "New Yorks". The "New Yorks" would eventually acquire the separate nicknames of the "Gothams" and then the "Giants". The Metropolitan club was referred to alternately as the "Metropolitan," "Metropolitans" or the "Mets". They were also referred to, on occasion, as the "Indians"