Martínez made his major league debut on June 20, 1998, as the starting second baseman for the Giants against the San Diego Padres.

Martínez started the 2005 season with the Detroit Tigers and was traded on June 9 to the Philadelphia Phillies alongside Ugueth Urbina for infielder Plácido Polanco.

His option was not picked up by the club after the 2007 season,[2] but on January 29, 2008, they signed him to a minor league deal with an invitation to spring training.

[3] He wound up assigned to the minor league Las Vegas 51s to start the 2008 season, but was injured and spent several months on the DL.

He eventually returned to the 51s, but was released by the Dodgers on July 24 and was signed by the New York Mets to a minor league deal.