By Hugh Bronstein

CARACAS (Reuters) - Baseball and President Hugo Chavez are both popular in Venezuela, but uncertainty about his policies is prompting major league teams to stop investing here while developing their Dominican Republic training camps.

Since coming to power in 1999, socialist "revolutionary" Chavez has nationalized big chunks of the economy. His mentor, Cuba's Fidel Castro, outlawed professional sports altogether.

Venezuela remains a top source of big league players, but the number of Major League Baseball (MLB) teams with their own training complexes in the country has fallen to five. A decade ago there were about three times as many.

"The fear is that from one day to the next they might approve laws or make decisions against professional sports that would affect our operations," said Oscar Garcia, a local scout for the Detroit Tigers, which still has a training camp here.

"The rules are not clear and the industry is afraid to invest in infrastructure such as the fields, gymnasiums and classrooms that a camp needs," he said. "We are operating on a day-by-day basis against whatever might happen."

Chavez often accuses the U.S. "empire" of plotting to invade OPEC-member Venezuela in order to take over its vast oil reserves. Washington dismisses such talk as nonsense.

The tensions have not stopped Venezuela from increasing its presence on MLB rosters. On 2011 Opening Day there were 62 major league players born in Venezuela, the most ever.

Baseball was brought to the country by U.S. oil workers early last century. Local TV is brimming with games broadcast from the United States and Chavez himself is a keen player who once dreamed of pitching in the majors.

Such dreams persist among boys tempted by the glory and fat paychecks that can go along with a U.S. baseball career.

"The truth is I don't pay a lot of attention to politics," said Jesus Ustariz, an 18-year-old third baseman from Caracas who has been training for two years at the Tigers' camp in Ciudad Alianza, Carabobo state.

"My only goal is to get into the big leagues."

Chavez also has a goal: to win another term in the October, 2012, election. The opposition vows to unify behind one candidate and the race could be tight, perhaps making it less likely that Chavez will announce any changes in regulations that might upset the popular sport ahead of the vote.

Still recovering from a June cancer operation, "El Comandante" says he'll be ready for a hard 2012 campaign.

PIRATES SHIP OUT

The Pittsburgh Pirates were the latest team to pull the plug on their Venezuela camp, leaving only the Tigers, the Philadelphia Phillies, Seattle Mariners, Tampa Bay Rays and Cincinnati Reds with their own academies in the country.

"Though the Pirates have not commented publicly on the situation, the instability and political climate in Venezuela is thought to have played a large role in the organization's decision to pull out," said a story this month on the Pirates official website.