Rockies reliever Josh Outman drilled the rookie in the head on Friday and Gregorius complained of soreness and headaches before the D-backs placed him on the seven-day disabled list with a mild concussion. A CT-scan came back normal, but the club opted to err on the side of caution.
Aside from being symptom-free, Gregorius had to pass a series of tests to be cleared that involved answering 20 questions correctly, then exercising under light distress and answering the questions again.
The 23-year-old is eligible to be activated Saturday, but Gibson said he wasn't sure yet whether that will happen on time.
Before the injury, Gregorius had hit safely in all seven games in which he appeared, going 11-for-27 with four doubles and two home runs.
Tyler Emerick is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.