For decades in Cuba under the Castro regime, which outlawed professional sports shortly after coming into power, athletes have been little more than government property, forced to compete more for national pride than for personal glory and big contracts.

That system, rigged as it is against the individual, forces elite talent such as the boxer Guillermo Rigondeaux – who fought in more than 400 amateur bouts and won Olympic gold medals in 2000 and 2004 – and Los Angeles Dodgers' outfielder Yasiel Puig to make a cruel decision: Flee or stay behind?

Rigondeaux, who will defend his super bantamweight title against the lightly-regarded Japanese fighter Hisashi Amagasa on Dec. 31, is one of many who opted for freedom and the chance at a professional title, but at what cost?

"Guillermo had to leave behind a wife and two kids," said Brin-Jonathan Butler, journalist and author of "A Cuban Boxer’s Journey: Guillermo Rigondeaux, From Castro’s Traitor to American Champion."

"His first attempt at defection split his parents… Almost every family has been split by this horrible decision that they all have to make," he told Fox News Latino.

That's why Butler decided to name his documentary about Cuban boxers, "Split Decision."

"If you want to enter the professional ranks and earn market value for your skills," Butler said, "the choice that’s been left to these athletes is to abandon their families, potentially forever, and to leave behind everything they’ve ever known."

Butler, a former amateur boxer himself who had gone to Cuba looking for a trainer, first met Rigondeaux in 2007, just after a failed attempt to defect in Brazil ended with him and another boxer being returned to Cuba in disgrace.

“The athlete who abandons his delegation is not unlike the soldier who abandons his fellow men in the midst of combat,” Fidel Castro himself wrote about the two athletes in Granma.

"I met him three months after that when he showed up at a gym where I was training," Butler recalled. "None of the Olympic coaches or even athletes who were there could talk to him, and they seemed frightened. I didn’t really understand what was going on. Fidel and Cuban sport had forbidden him from even talking to athletes who had been best friends of his."

The Cuban boxing program has always been about more than mere athletic achievement. "Castro always used the boxers as a symbolic war against American values," Butler said, "to demonstrate that they fight for something more than money."

The most famous examples are heavyweights Teófilo Stevenson and Félix Savón, who were offered millions of dollars to fight Muhammad Ali and Mike Tyson respectively, but both decided to stay.

"[Rigondeaux] looked at the lives of these great champions," Butler told FNL, "and he said, 'I don't want that to be me ... I want a chance to compete.'"

But the lure of money has permeated the Cuban system anyway, in a horrible way, creating what Butler calls "a modern slave state."

"Cuban athletes represent the most expensive human cargo on earth," he explained. "They are sitting on over a billion dollars of human capital if these boxers and baseball players would come over to any other field or ring in the world and begin to ply their trade."

The recent decision to try to normalize relations between the U.S. and Cuba, may affect the number of fighters who defect, Butler believes, but not in the way many might think.

In Cuba, there are today around 20,000 boxers employed by the state, and, Butler said, the younger guys are asking themselves, "What’s in it for me?"

"That sense of individualism," he said, "is going to bring a real rip tide of youth."