Samuel (ribs/knee) officially didn't practice Thursday, Nick Wagoner of ESPN.com reports.
There was a brief sighting of Samuel during the portion of the session open to the media, when Cam Inman of The San Jose Mercury News noted the wide receiver left the early walkthrough and went to the 49ers' weight room. Both Samuel and Jauan Jennings (shin) were non-participants Thursday, while Brandon Aiyuk (shoulder) was limited, so Friday's injury report likely will be key to determining who among the trio may be available Sunday against the Cardinals.