Nunez began his career with the Toronto Blue Jays in 1994 and made his Major League debut with the Pittsburgh Pirates in 1997. His best season came in 2005 when he batted .285 with five home runs and 44 RBIs in a career-high 139 games for the NL Central-champion St. Louis Cardinals. Nunez has appeared in 100-plus games in seven different Major League seasons, including both 2006 and 2007 with the Philadelphia Phillies.
Over his career the versatile infielder has played more than 250 Major League games at second base, third base, and shortstop. Overall, Nunez sports a .242 Major League average and a .264 mark in the minors.