Martinez, 24, was batting .178 with 11 doubles and 13 RBIs in 60 games this season with Chicago's Triple-A affiliate, the Charlotte Knights of the International League. He appeared in the Majors in each of the last two seasons, batting .258 with four doubles, a triple and three RBIs in 34 combined games with the Marlins in 2010 and 2011.
He was one of two players sent to the White Sox as compensation for the signing of manager Ozzie Guillen. Martinez, a Puerto Rican native, was drafted out of Porterville Junior College in California in the 11th round in 2006. He scored 90 runs and hit .302 at Double-A Jacksonville in 2010.
With Elian Herrera and Luis Cruz in the Major Leagues, and Dee Gordon and Justin Sellers on the disabled list, Martinez will provide middle infield depth at Triple-A.
Ken Gurnick is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.