Carlos Alfonso Guillén (born September 30, 1975) is a former Venezuelan professional baseball infielder.Guillén was signed by the Houston Astros as a non-draft amateur free agent in 1992. He was traded to the Seattle Mariners with pitcher Freddy García and John Halama in the deal that sent Randy Johnson to the Astros. Guillén made his debut in 1998 and was traded to Detroit at the end of the 2003 season. He retired after the 2011 season.