(CNN) "Sport is the conquest of the revolution," reads the sign looming over the outfield of Havana's Estadio Latinoamericano, the island's main stadium and hallowed ground for Cuban baseball fans.

There are no beer ads or Nike banners in the stadium, no advertising for anything but the Cuban revolution. Tickets cost a mere 15 cents. There aren't any beer sales either. Fans instead drink sugary cafecitos while smoking Cuban cigars.

The bare-bones stadium is the setting of one President Barack Obama's most anticipated events during his historic visit: taking in a baseball game between the Cuban National Team and the Tampa Bay Rays on Tuesday.

"Play ball!" Obama tweeted after Major League Baseball announced he would attend the game.

He'll observe the sporting event after a morning in which he gives a major address, to be televised on Cuban state-run TV, in which he will lay out the new U.S. policy on Cuba. Afterwards, he is scheduled to meet with Cuban dissidents.

While Cuban baseball players are world famous for their talent, Obama's visit comes as Cuba's favorite pastime struggles to survive a crippling spree of defections.

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When Fidel Castro -- himself an avid baseball fan -- was president of Cuba, players faced a lifetime ban from the country if they left the island to play for huge sums in the U.S.

But Castro's younger brother and successor, Raul, has been more pragmatic when it comes to the island's national past time.

Under Raul Castro, Cuban baseball players have been allowed to play in leagues in countries like Mexico and Japan. Some defectors have been allowed to return to visit Cuba sfter years of being shut out.

Even with the relaxation of some restrictions, though, the number of defections has surged.

According to Cuban officials, up to 150 players have left the island in the last year, many employing human smugglers and criminal gangs to flee to the U.S.

"It's not only the enticement of the money for these young players to leave, but also, they don't have the same status at home that they used to have," Baseball author Peter Bjarkamn told CNN. "The guys that used to be branded as traitors and still are to some degree by the government, for the fans these guys are the heroes."

Up until recently, Cubans almost had no way of following the careers of defectors after they left the island. Cuban state-run TV would not show American games where Cuban players competed and home Internet access remains a rarity.

Photos: President Obama visits Cuba Photos: President Obama visits Cuba U.S. President Barack Obama attends a baseball game in Havana, Cuba, with his family and Cuban President Raul Castro, right, on Tuesday, March 22. The Cuban national team was playing an exhibition against Major League Baseball's Tampa Bay Rays. Obama is the first U.S. President to visit Cuba since Calvin Coolidge in 1928. Hide Caption 1 of 19 Photos: President Obama visits Cuba Tourists in a Havana antique shop watch Obama give a speech on March 22. Hide Caption 2 of 19 Photos: President Obama visits Cuba Obama waves to the crowd before delivering his speech at the Grand Theater in Havana on March 22. In his speech, Obama urged Cubans to look to the future with hope, casting his historic visit as a moment to "bury the last remnants of the Cold War in the Americas." Hide Caption 3 of 19 Photos: President Obama visits Cuba First lady Michelle Obama and her daughter Malia stand with children of U.S. Embassy workers after dedicating a bench and two magnolia trees at a small park in Havana on March 22. Hide Caption 4 of 19 Photos: President Obama visits Cuba The Obamas pose with Castro before a state dinner in Havana on Monday, March 21. Hide Caption 5 of 19 Photos: President Obama visits Cuba U.S. Secretary of State John Kerry, right, speaks with Cuban First Vice President Miguel Diaz-Canel ahead of the state dinner on March 21. Hide Caption 6 of 19 Photos: President Obama visits Cuba Castro tries to lift up Obama's arm at the end of a joint news conference on March 21. Hide Caption 7 of 19 Photos: President Obama visits Cuba Obama meets with Castro in Havana on March 21. Hide Caption 8 of 19 Photos: President Obama visits Cuba Michelle Obama speaks with Cuban girls during a Let Girls Learn roundtable in Havana on March 21. Hide Caption 9 of 19 Photos: President Obama visits Cuba Obama lays a wreath at the Jose Marti monument in Havana's Revolution Square on March 21. "It is a great honor to pay tribute to Jose Marti, who gave his life for independence of his homeland," Obama wrote after he laid the wreath. "His passion for liberty, freedom, and self-determination lives on in the Cuban people today." Hide Caption 10 of 19 Photos: President Obama visits Cuba Backdropped by a monument depicting revolutionary hero Che Guevara, Obama listens to the U.S. national anthem during the wreath-laying ceremony on March 21. Hide Caption 11 of 19 Photos: President Obama visits Cuba Obama and Castro review troops before bilateral meetings on March 21. Hide Caption 12 of 19 Photos: President Obama visits Cuba Obama walks up the stairs of the Palace of the Revolution on March 21. Hide Caption 13 of 19 Photos: President Obama visits Cuba Obama and members of the first family take a walking tour of a Havana cathedral on Sunday, March 20. Hide Caption 14 of 19 Photos: President Obama visits Cuba The first family stops to look at a painting of Abraham Lincoln in the Museum of the City of Havana on March 20. Hide Caption 15 of 19 Photos: President Obama visits Cuba Obama's convoy drives along the Malecon sea wall on March 20. Hide Caption 16 of 19 Photos: President Obama visits Cuba The President and first lady greet families of embassy personnel on March 20. Hide Caption 17 of 19 Photos: President Obama visits Cuba Obama waves shortly after arriving at Jose Marti International Airport. Hide Caption 18 of 19 Photos: President Obama visits Cuba Obama and his family exit Air Force One on March 20. Hide Caption 19 of 19

But Cubans increasingly watch U.S. baseball games via thumb drives brought into the country and passed from fan to fan. Or they can see the latest scores at new public WiFi hotspots that have opened around the country.

Many Cuban fans complain that the level of play in Cuba doesn't compare to games in the U.S. and that, devastated by the defections, the Cuban National Team no longer dominates international competitions.

"Our baseball is dying on us," was the title of a 2015 editorial in a state-run Cuban newspaper that typically shies away from any criticism of officialdom.

To recover from the slump, Cuba has reversed course and begun negotiating with Major League Baseball to allow Cuban peloteros, or baseball players, to suit up in both countries.

Last December, MLB officials and players, including Cuban defectors, flew to Havana for a training clinic with Cuban children and to meet government representatives about a possible agreement.

Greeting the players at the airport was Cuban baseball official Tony Castro, one of Fidel Castro's sons.

MLB hopes to create a "a safe and legal path for Cuban baseball players who desire to play in major league baseball to reach the major leagues," Dan Halem, the league's chief legal officer, told reporters.

On Tuesday, a week before Obama is set to attend the baseball game in Havana, U.S. Treasury officials announced new measures that would allow Cubans to receive salaries in the U.S. , paving the way for Cuban baseball players to potentially join the major leagues without having to defect first.

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The announcement came months after MLB presented a proposal to the Treasury on how it hoped to compensate Cuban players while not running afoul of the longstanding trade embargo enacted by Congress.

Ben Rhodes, Obama's deputy national security adviser, told reporters Wednesday that work still remained on negotiating a deal between MLB and the Cuban government for signing players directly on the island.

But he said the groundwork was in place to deepen ties in an area where Cubans and Americans have long aligned.

"Baseball is obviously something that the United States and the Cuban people share a common love of and it's a part of both of our heritages, and frankly, also part of the type of exchanges that we are pursuing in business, in culture, in the arts, in sports that can bring the American and Cuban people closer together," Rhodes said.

At a recent baseball game in Havana, former player Geronimo Diaz said he hoped the changes would not just take the best players from Cuba but also breath new life into the island's beloved sport.

"Over there is where they have the best instructors," Diaz said. "Baseball there is more alive, it's stronger. If there's an agreement, maybe it will improve baseball in Cuba, too."