Williams (concussion) remained absent from practice Friday, Kyle Meinke of MLive.com reports.
Williams has been unable to practice at all this week and remains in concussion protocol after taking a hit to the head in the season opener against San Francisco. The wide receiver has an extra day to heal up with Detroit's next game coming Monday against the Packers, but that doesn't seem like it will be enough time for him to get back on the field given the lack of progress in his recovery up to this point.