The White Sox selected Cannon's contract from Triple-A Charlotte on Tuesday.
Cannon has made two starts so far in the minors, allowing three earned runs across 9.2 innings while striking out 11 batters and walking five. He will start Tuesday's game against the Royals, though the 23-year-old righty will most likely be sent back to Charlotte after making his MLB debut. In order to make room for Cannon, Jared Shuster was optioned to Triple-A, and Josimar Cousin was designated for assignment.