Lynn had been sidelined by right knee inflammation. The 34-year-old Lynn is slated to start Sunday against the Boston Red Sox.
Right-hander Jimmy Lambert was optioned to Triple-A Charlotte. Lambert got his first big league win Tuesday night at Oakland, pitching five innings of one-run ball in Chicago's 6-3 victory.
Lynn was acquired in a trade with Texas in December. He is 10-4 with a 2.59 ERA in 24 starts in his first season with the American League Central-leading White Sox.
Lynn last pitched for Chicago on Aug. 28, allowing seven runs in five innings in a 7-0 loss to the Cubs.