Manager Buck Showalter said Hammel will not be throwing off the mound, but will be on a slight incline in order to "test the knee a little bit."
"If that goes well, [pitching coach Rick Adair] and the trainers have a schedule set up for him starting on Monday and Thursday, where he actually throws off the rubber," Showalter said. "So, we'll see how tomorrow goes. That's the plan on him."
Hammel, an All-Star Final Vote candidate, had pitched to a 3.54 ERA before the injury.
Because Hammel's injury hasn't impacted his arm strength, Showalter believes the right-hander could return to the rotation relatively quickly, as long as his knee can withstand the workload.
"Once he gets healthy, it can move pretty quickly," Showalter said. "It's not like he's going to have to go out and throw one or two innings the first time out, and then two or three innings the next time out."
Showalter said more important than working off the incline on Saturday will be how the knee responds to that work on Sunday.
"If he doesn't have any issues there, then we can proceed with the plan to have a little more definitive date about when he'll be able to pitch for us," Showalter said.