The White Sox and Colon have agreed to a one-year deal, according to major-league sources.
The deal is pending a physical.
Colon, who pitched a career-high 242 innings for the White Sox in 2003, managed only 39 innings with the Red Sox during an injury-plagued 2008.
Colon will compete for a spot in the White Sox rotation, which lost Javier Vazquez to free agency, but still has Mark Buehrle, John Danks, Gavin Floyd and Jose Contreras coming off injury. Youngster Aaron Poreda is also in the mix for a rotation spot.
Colon started seven games for the Red Sox and won of four of them. He injured his back in June during a start against the Phillies after taking several violent hacks during an at-bat against Cole Hamels.
He was placed on the disabled list and rehabbed at Class AAA Pawtucket before returning for a start on Sept. 13 against the Blue Jays.
The Red Sox suspended Colon without pay on Sept. 19 after he left the team to return to the Dominican Republic. He had been upset with the Sox's decision to use him out of the bullpen.
Colon went 15-13 with a 3.87 ERA for the White Sox in 2003.