Roberts (forearm) tossed a perfect inning in a rehab appearance Sunday with Triple-A Iowa.
Roberts needed just 10 pitches (seven strikes) to retire the side in what was his first game action at any level since June 28. Cubs manager Craig Counsell hasn't provided word on the next steps for Roberts, but the right-hander may not need any further rehab appearances before returning from the 15-day injured list. MLB.com currently lists Roberts as its probable starter for Tuesday's game against the Tigers, though if he's activated for that contest, he would likely work just an inning or two before David Peterson takes over in bulk relief.