Known primarily for his speed, Ruan was signed as an undrafted free agent by the Montreal Expos on November 15, 1996.

Against more experienced U.S. pitchers he struggled slightly, hitting only .239 for the Gulf Coast Expos that season, though he still stole 13 bases.

On March 23, 2002 he was traded by the Expos to the Los Angeles Dodgers along with pitcher Guillermo Mota for Jorge Nunez and Matt Herges.

On July 2, he was signed as a minor league free agent by the Kansas City Royals and sent to their Double-A team in Wichita where he rebounded slightly, hitting .276 with 11 steals.

He became a free agent at the end of the season and signed a minor league contract with the Philadelphia Phillies on December 17, 2008.