Prior, who is recovering from a strained shoulder suffered in March, said after his last outing he felt he could've gone another inning, but he was limited by a strict pitch count.
Not only does Prior plan to "throw" more, he also plans to "pitch" more on Saturday.
"I'm still going to concentrate on throwing first-pitch strikes -- throwing two out of three for strikes -- but probably I'll try to pitch a little bit more," Prior said. "I think I only threw for fastballs and for changeups. I'll try to incorporate things like pitching backwards, throwing breaking balls where I'm accustomed to throwing breaking balls."
On Wednesday, Prior said he wasn't feeling sore from his work on Monday.
Prior gave up three runs, two earned, in his two innings against the Kane County Cougars on Monday.
Cubs manager Dusty Baker said Minor League rehab starts are anything but easy.
"Anybody that's been in baseball knows the toughest guys to pitch against are Minor League guys," Baker said. "Those kids are out there swinging."
Prior will face the Fort Wayne Wizards at O'Brien Field in Peoria, Ill., at 6:30 p.m. CT on Saturday.
Ryan Crawford is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.