The team announced they have signed the 27-year-old to a minor league deal and he is expected to pitch at Triple-A Charlotte after a stint at extended spring training in Arizona.
Hanson went to spring training with the Texas Rangers this year, but was released after posting a 6.43 Cactus League ERA over 14 innings. He made four appearances (two starts) in Arizona.
After posting a 2.89 ERA over 21 starts in his rookie season of 2009, Hanson has slipped each season thereafter. He had a 3.33 ERA over 34 starts in 2010, a 3.60 mark in 22 starts in 2011, a 4.48 ERA in 31 starts in the 2012 season and a 5.42 ERA in just 15 outings (13 starts) last season.
Once named the top overall prospect in the Braves' organization, according to Baseball America, Hanson has gone through a gradual decline in velocity since his rookie season. He dealt with shoulder issues that kept him on the disabled list in 2011.
After an underachieving season last year, the White Sox have started to rebuild the roster and in the process cut some $27 million from the roster commitment they made on Opening Day of 2013. In the midst of searching for young long-term solutions, they have also gambled on some low-price veteran alternatives.
Felipe Paulino, who made his second start with the White Sox on Monday night at Colorado, was signed for a guaranteed $1.75 million this season, even though he hadn't pitched in the major leagues since 2012.
In the bullpen, the White Sox took a chance on right-hander Ronald Belisario, signing him to a one-year, $3 million deal. The Los Angeles Dodgers could have brought Belisario back for significantly less, but non-tendered him instead, making him a free agent.