The final significant baseball event of 2015 was not the Royals' World Series victory or Cubs' signing of Jason Heyward, but rather last month's visit to Cuba by eight major-league players and officials from Major League Baseball and the MLB Players Association.

The trip was a resounding success -- personally (for those who went), culturally (because of connections made with the Cuban people), and commercially (to the extent that MLB and the union are more familiar with the economic possibilities, if the U.S. embargo ends).

In many ways, Cuba is the exemplar of baseball's future in this hemisphere at the outset of 2016: MLB and the MLBPA recognize the opportunity, but they can't be certain of what will come next. The same is true for the sport's prospects in Mexico, albeit for different reasons.

This much is clear: 2016 can be a watershed year for baseball's international growth, if MLB and the MLBPA partner effectively amid collective bargaining negotiations scheduled to begin this spring.

A synopsis of the packed schedule:

MLB/MLBPA-operated World Baseball Classic qualifying tournaments in Australia, Mexico and Panama in February and March, followed by another in Brooklyn in September.

a possible trip by the Tampa Bay Rays to Cuba for two exhibition games in March.

●— a Houston Astros-San Diego Padres spring training game in Mexico City.

two regular-season games between the Pittsburgh Pirates and Miami Marlins in San Juan, Puerto Rico, to honor Roberto Clemente Day.

off the field, ongoing discussions between MLB and the MLBPA about playing a series in London as soon as 2017.

"The Players and the MLBPA remain committed to growing the game globally -- both in terms of participation and popularity -- by working closely with MLB to strategically identify opportunities and locations that have the potential to provide long-term support and sustainability for the sport," MLBPA spokesman Greg Bouris said this week in a statement to FOX Sports. "What may eventually occur in this area in 2016 is the result of the sport's dedication to exposing the world to the great game of baseball, and we expect this growth to continue year after year."

Globally, the most important development could occur during a competition at which no baseball games are scheduled: the 2016 Summer Olympic Games in Rio De Janeiro, where the International Olympic Committee will vote on baseball's candidacy for the 2020 Tokyo Games. (Baseball and softball were last contested at the Olympics in 2008.)

While there's no sign MLB will reverse its precedent and allow current major leaguers to compete, inclusion in the Olympics is crucial for another reason: In many countries where baseball is at an early developmental stage, government funding is higher for Olympic sports than non-Olympic sports. "The return of baseball to the Olympics could be the key to exploding baseball's popularity worldwide," Riccardo Fraccari, president of the World Baseball Softball Confederation, said in an interview last year.

Closer to home, while Cuba is the subject of understandable fascination and debate, the coming year could be even more transformative for Mexico.

MLB commissioner Rob Manfred made a well-publicized visit to Mexico last year and has spoken publicly about the possibility of a permanent MLB franchise based in Mexico. Most notably, in early October he told Maury Brown of Forbes, "We see Mexico as an opportunity internationally. We also think a team in Mexico and a larger number of Mexican players in the big leagues could really help us continue to grow the Hispanic market in the United States."

MLBPA executive director Tony Clark said last year that the union would be "engaged and interested" about the possibility of a Mexican MLB franchise. The union obviously loves the notion of expansion, because that means 25 new big-league jobs -- and more likely 50, considering MLB would want to maintain an even number of teams. But some players may be reluctant to vote in favor of living and working in Mexico for half the year, which is why events such as the Astros-Padres exhibition are essential in helping to shape perceptions.

Long before an MLB franchise in Mexico City becomes a reality, MLB must make meaningful progress on another aspect of Manfred's statement to Brown: development of the Mexican talent pool. Twelve Mexican-born players appeared in the majors last year, only one of whom (Atlanta's Daniel Castro) was a position player.

Mexico's amateur market is inefficient, because local Mexican League clubs sign prospects as teenagers and then charge release fees to MLB clubs -- a tremendous disincentive for MLB teams to invest there, in comparison to relatively unfettered markets in the Dominican Republic and Venezuela. Mexican League teams won't relinquish those rights easily, so it will be up to MLB and MLBPA negotiators to propose a comprehensive -- and unified -- strategy on player movement that recognizes Mexican interests, as with the current Japanese posting system.

Soccer is Mexico's primary national sport, of course, and no amount of work by MLB or the MLBPA will change that. But with improving infrastructure and a population 10 times greater than that of the Dominican Republic, Mexico has vast baseball potential. By the end of a pivotal 2016, MLB and its stakeholders must develop a firmer grasp of what that means.