Vazquez told the Pittsburgh Post-Gazette on Monday that he legally changed his surname to match that of his sister, Prescilla.
The 26-year-old from Venezuela took over as Pittsburgh's closer last season and saved 21 games with a 1.67 ERA. His uniform will reflect the change soon, though Rivero said Monday he wasn't sure when. He apologized on Twitter to fans who had purchased his No. 73 jersey with his name on the back.
Vazquez lives with his sister in Florida during the offseason, and she has advised him on a number of career decisions, including when he dropped Scott Boras as his agent this offseason. Vazquez says his sister was a primary negotiator for his new contract with the Pirates, which was signed in January and could keep him with Pittsburgh until 2023.
Vazquez says he might also change his jersey number next season -- if Prescilla wants him to.
"When she says it's time to change my number, I'll do it," he told the Post-Gazette.