With Cade Horton (forearm) set to land on the injured list, Assad is an option to get promoted from the minors and fill his rotation spot, Jordan Bastian of MLB.com reports.
Horton departed Friday's contest after only an inning of work due to right forearm discomfort, and he will be examined more fully to determine the extent of the injury. Following a rainout Saturday, the Cubs don't have to worry about Horton's spot in the rotation again until Wednesday. Assad is a candidate to get the call from Triple-A Iowa, though it appears to be more likely that Ben Brown or Colin Rea moves over from the bullpen and into the rotation. Even if Assad isn't needed right away, he could be next in line if any other Chicago pitchers go down.