After spending five years in the Twins organization, he was claimed off waivers by the Arizona Diamondbacks on Jan. 19, 2007.

On April 3, 2008, Romero recorded his first career RBI, when he hit a sacrifice fly as a pinch hitter.

In 2012, while playing for Tigres de Quintana Roo, was tested positive for doping and suspended for 50 games to serve in 2013.

He signed a minor league deal with the San Francisco Giants on February 22, 2016.

Romero signed with the Rojos del Águila de Veracruz of the Mexican Baseball League for the start of the 2016 season.