Samuel (hamstring) was a non-participant at Thursday's practice, Sam Warren of The Athletic reports.
Prior to the 49ers' Week 8 bye, head coach Kyle Shanahan expressed optimism that Samuel may be able to return in Week 9, but the tide turned Thursday, when GM told KNBR radio that the wide receiver isn't likely to play Sunday against the Raiders, according to Matt Maiocco of NBC Sports Bay Area. With two DNPs under his belt so far and one more chance to practice Friday, Samuel appears to be in line for his third missed game in a row due to a right hamstring injury.