"We've been plenty surprised every step of the way," Ellis said of his rapid rehab.
Ellis has backed off only with running, which is how he injured the knee two weeks ago. He also hasn't thrown to bases coming out of the crouch.
"The final hurdles," he said. "But as far as [other] baseball stuff, I feel 100 percent. Squatting never bothered me before. Just running, you know, my explosiveness."
The original estimate on Ellis's rehab was four to six weeks.
"I hope four is on the high side, the way I feel," he said. "Maybe I'll get out [on a Minor League rehab assignment] sometime soon."
Ken Gurnick is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.