The White Sox activated Cannon (back) from the 15-day injured list ahead of his start Sunday against the Giants.
The right-hander has been sidelined most of June due to a lower-back strain, but he's ready to rejoin Chicago's rotation after one rehab game. Cannon threw 48 pitches over three scoreless innings with Triple-A Charlotte on Tuesday, so he's likely to have some workload limitations in his first couple starts back with the White Sox.