John Danks, who has spent the last month and a half on the disabled list with shoulder soreness, will undergo exploratory surgery and miss the rest of the season.
His status for 2013 won't be known until after the surgery.
Danks' name came up in trade rumors after last season, but the White Sox felt good enough about his arm in December to sign him to a five-year, $65 million extension through 2016.