Drabek, a former top prospect for Toronto, has appeared in only 39 games (30 starts) since breaking into the bigs in 2010, posting an 8-15 record and 5.27 ERA in 172.1 career major-league innings. The 27-year old was originally traded to Toronto by the Phillies as a main piece of the return for Roy Halladay, but injuries and inconsistency has limited his success in the major leagues.
Drabek spent the majority of the last two seasons in the minors, posting a 3.14 ERA in 43 innings in 2013 before taking a step back and putting up a 4.18 ERA mark in 99 innings last season. He worked mostly in relief for the Jays' Triple-A affiliate last year, though it is unclear if the White Sox intend to use him as a starter or reliever.
Drabek is out of minor-league options, meaning that the White Sox would have to get him through waivers to send him to the minors at any point during the season. He has about a week to compete for a spot on Chicago's major-league club, or could be on the move again through the waiver process.