Hellickson said Wednesday morning that the hamstring felt 90 to 95 percent.
"I can do everything, [including] running," Hellickson said, "but I don't know when I'll get on the mound."
"He was out there jogging pretty good today," manager Joe Maddon said.
Last Thursday, Hellickson felt the hamstring bother him while warming up for a bullpen session.
On Wednesday, Hellickson was named the game's sixth-best prospect by Baseball America.