The White Sox optioned Dunning (elbow) to Double-A Birmingham on March 6.
Dunning is still on the mend from March 2019 Tommy John surgery, so he wasn't a legitimate candidate to break camp with the big club. Once he's deemed ready for game action, Dunning will likely make at least a couple starts at extended spring training or one of the White Sox's lower-level affiliates before making his 2020 debut with Birmingham.