Zárate signed a minor league contract with the Toronto Blue Jays on January 26, 2005. Zárate played for the Blue Jays minor league system through the 2008 season. He began 2009 with the GCL Blue Jays. The Blue Jays released Zárate on April 15, 2009.
Hanshin Tigers
Zárate played for the Hanshin Tigers of Nippon Professional Baseball in 2012. He made his NPB debut on August 5, 2012. He also played the 2013 season for Hanshin before becoming a free agent after the season.
On January 21, 2015, Zárate signed a minor league contract with the Tampa Bay Rays that included an invitation to Spring Training.[3] He elected free agency on November 6, 2015.
Pittsburgh Pirates
On December 7, 2015, Zárate signed a minor league deal with the Pittsburgh Pirates organization that included an invitation to Spring Training.[4] He spent the 2016 season with the Indianapolis Indians before his release on June 13, 2016.
Cleveland Indians
On January 4, 2018, Zarate signed a minor league contract with an invitation to spring training with the Cleveland Indians.[5] He pitched for the Triple-AColumbus Clippers, appearing in 29 games as a reliever and finishing with a 3-1 record, 3.30 ERA, and 40 strikeouts. He was released by the organization on July 23, 2018.
He was traded to the Leones de Yucatán on August 15, 2018. He became a free agent following the season.
On January 28, 2020, Zárate signed with the Rieleros de Aguascalientes of the Mexican League. Zárate did not play in a game in 2020 due to the cancellation of the Mexican League season because of the COVID-19 pandemic.[6] He later became a free agent.
^Topkin, Marc. "Rays manager Kevin Cash plans more stable lineup,"Tampa Bay Times (February 7, 2015): "If LHP Robert Zarate contributes, credit the Rays' international scouts, who saw the 28-year-old Venezuelan pitch last year for a Japanese independent league club, the Gunma Diamond Pegasus."