Samuel (quadriceps) wasn't spotted during the portion of Thursday's practice open to the media, Cam Inman of The San Jose Mercury News reports.
After coach Kyle Shanahan said Samuel was slated for a limited session Wednesday, the wide receiver upheld that statement once the 49ers posted their first Week 13 practice report. However, Samuel's quad issue appears to be keeping him off the field one day later, which will be confirmed, one way or another, later Thursday. With the state of the team's backfield in flux with Elijah Mitchell again sidelined with a sprained MCL and Christian McCaffrey tending to a knee injury, an active Samuel could get more work in the role that he played in the second half of last season when the team plays Sunday versus the Dolphins. Still, McCaffrey did mix into drills Thursday, so the overall situation should continue to be monitored.