Ronald J. Belisario (last name sometimes spelled Belizario) (born December 31, 1982) is a Venezuelan former professional baseball pitcher.

He played in Major League Baseball (MLB) for the Los Angeles Dodgers, Chicago White Sox and Tampa Bay Rays.

He was placed on the Marlins 40 man roster in September 2004 but missed the 2005 season because of undergoing Tommy John surgery on his right elbow.

Belisario made his Major League debut on April 7, working one scoreless inning as a relief pitcher against the San Diego Padres.

He pleaded guilty to a lesser charge through his attorney but did not report to spring training until March 27, at which point he was placed on the restricted list.

For the third year in a row, Belisario did not report on time for spring training in 2011 due to problems in Venezuela.

[4] On December 20, 2011, Belisario's agent stated that he had gotten a five-year visa and would be in Arizona on time for the start of 2012 spring training.

[6] In February, Belisario admitted that he had not been able to obtain a visa in 2011 because he had tested positive for cocaine, which had also led to his suspension.

[7] After serving his suspension, and a handful of minor league appearances, Belisario finally rejoined the Dodgers when he was activated off the restricted list on May 3, 2012.

[13] On May 24, Belisario entered a game in which the White Sox lead the New York Yankees 3–0, after 8 shutout innings by starter John Danks.

The White Sox would go to the bottom of the 9th inning now tied 3-3, as Belisario was hailed with boos leaving the field.

[15] However, in a game against the Cleveland Indians on May 26, Belisario was passed up on a save opportunity in favor of fellow reliever Scott Downs.