The baseball games between the New York Mets and the Florida Marlins at Hiram Bithorn Stadium in San Juan, Puerto Rico, are proof enough that major league baseball can be played there. Seeming infinitely better than defunct Montreal Expos' original home of Jarry Park, which I visited as a kid in 1970 just to see Rusty Staub, the park would be a sufficient venue for Major League Baseball games.
A flight from New York City to San Juan, Puerto Rico, takes approximately three and a half hours. That is less time than if you were flying from JFK to LA or San Francisco. Baseball teams would not have a problem getting there, and the surrounding area is amenable for the players when not on the field.
Watching the three games of this series (which the Marlins took 2-1), I noticed that every seat in the house was taken. Even on Thursday night, after a twenty minute rain delay, the place was packed. The crowds are enthusiastic; they are baseball savvy and certainly deserve a team of their own for a number of reasons.
First, according to the Baseball Almanac, there has been a rich history of players from Puerto Rico or of Puerto Rican descent in the Major Leagues, including Hall of Famer Roberto Clemente. Currently, the Mets alone have Angel Pagan, Jesus Feliciano, Alex Cora, Pedro Feliciano, and the injured Carlos Beltran. This certainly gives the local fans an incentive to come out and see the games on a regular basis.
Second, besides Puerto Rico, the region is a spawning ground for Major League Baseball players. Think especially of Cuba and the Dominican Republic. There would be an interest of people in those neighboring countries to come to Puerto Rico to see baseball games. This would encourage tourism and inspire more local prospects to bring their talents to the game.