The Rockies also got cash considerations from the White Sox, who got right-handed prospect Brandon Hynick in return.
Contreras, 37, was 5-13 with a 5.42 ERA in 21 games for the White Sox this season.
He's 70-63 with a 4.66 ERA in 184 games (173 starts) for his career. He also pitched for the Yankees (2003-04).
Hynick, 24, was 10-9 with a 3.83 ERA in 26 starts for Class AAA Colorado Springs this year.
Copyright 2009 by United Press International.